module.c

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/*
   Copyright (C) 2002 Richard Henderson
   Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include <linux/export.h>
#include <linux/moduleloader.h>
#include <linux/ftrace_event.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <linux/rcupdate.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/vermagic.h>
#include <linux/notifier.h>
#include <linux/sched.h>
#include <linux/stop_machine.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/rculist.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <linux/license.h>
#include <asm/sections.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
#include <linux/async.h>
#include <linux/percpu.h>
#include <linux/kmemleak.h>
#include <linux/jump_label.h>
#include <linux/pfn.h>
#include <linux/bsearch.h>
#include <linux/fips.h>
#include "module-internal.h"

#define CREATE_TRACE_POINTS
#include <trace/events/module.h>

#ifndef ARCH_SHF_SMALL
#define ARCH_SHF_SMALL 0
#endif

/*
 * Modules' sections will be aligned on page boundaries
 * to ensure complete separation of code and data, but
 * only when CONFIG_DEBUG_SET_MODULE_RONX=y
 */
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
# define debug_align(X) ALIGN(X, PAGE_SIZE)
#else
# define debug_align(X) (X)
#endif

/*
 * Given BASE and SIZE this macro calculates the number of pages the
 * memory regions occupies
 */
#define MOD_NUMBER_OF_PAGES(BASE, SIZE) (((SIZE) > 0) ?     \
        (PFN_DOWN((unsigned long)(BASE) + (SIZE) - 1) - \
             PFN_DOWN((unsigned long)BASE) + 1) \
        : (0UL))

/* If this is set, the section belongs in the init part of the module */
#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))

/*
 * Mutex protects:
 * 1) List of modules (also safely readable with preempt_disable),
 * 2) module_use links,
 * 3) module_addr_min/module_addr_max.
 * (delete uses stop_machine/add uses RCU list operations). */
DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);
#ifdef CONFIG_KGDB_KDB
struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
#endif /* CONFIG_KGDB_KDB */

#ifdef CONFIG_MODULE_SIG
#ifdef CONFIG_MODULE_SIG_FORCE
static bool sig_enforce = true;
#else
static bool sig_enforce = false;

static int param_set_bool_enable_only(const char *val,
                      const struct kernel_param *kp)
{
    int err;
    bool test;
    struct kernel_param dummy_kp = *kp;

    dummy_kp.arg = &test;

    err = param_set_bool(val, &dummy_kp);
    if (err)
        return err;

    /* Don't let them unset it once it's set! */
    if (!test && sig_enforce)
        return -EROFS;

    if (test)
        sig_enforce = true;
    return 0;
}

static const struct kernel_param_ops param_ops_bool_enable_only = {
    .set = param_set_bool_enable_only,
    .get = param_get_bool,
};
#define param_check_bool_enable_only param_check_bool

module_param(sig_enforce, bool_enable_only, 0644);
#endif /* !CONFIG_MODULE_SIG_FORCE */
#endif /* CONFIG_MODULE_SIG */

/* Block module loading/unloading? */
int modules_disabled = 0;
core_param(nomodule, modules_disabled, bint, 0);

/* Waiting for a module to finish initializing? */
static DECLARE_WAIT_QUEUE_HEAD(module_wq);

static BLOCKING_NOTIFIER_HEAD(module_notify_list);

/* Bounds of module allocation, for speeding __module_address.
 * Protected by module_mutex. */
static unsigned long module_addr_min = -1UL, module_addr_max = 0;

int register_module_notifier(struct notifier_block * nb)
{
    return blocking_notifier_chain_register(&module_notify_list, nb);
}
EXPORT_SYMBOL(register_module_notifier);

int unregister_module_notifier(struct notifier_block * nb)
{
    return blocking_notifier_chain_unregister(&module_notify_list, nb);
}
EXPORT_SYMBOL(unregister_module_notifier);

struct load_info {
    Elf_Ehdr *hdr;
    unsigned long len;
    Elf_Shdr *sechdrs;
    char *secstrings, *strtab;
    unsigned long symoffs, stroffs;
    struct _ddebug *debug;
    unsigned int num_debug;
    bool sig_ok;
    struct {
        unsigned int sym, str, mod, vers, info, pcpu;
    } index;
};

/* We require a truly strong try_module_get(): 0 means failure due to
   ongoing or failed initialization etc. */
static inline int strong_try_module_get(struct module *mod)
{
    if (mod && mod->state == MODULE_STATE_COMING)
        return -EBUSY;
    if (try_module_get(mod))
        return 0;
    else
        return -ENOENT;
}

static inline void add_taint_module(struct module *mod, unsigned flag)
{
    add_taint(flag);
    mod->taints |= (1U << flag);
}

/*
 * A thread that wants to hold a reference to a module only while it
 * is running can call this to safely exit.  nfsd and lockd use this.
 */
void __module_put_and_exit(struct module *mod, long code)
{
    module_put(mod);
    do_exit(code);
}
EXPORT_SYMBOL(__module_put_and_exit);

/* Find a module section: 0 means not found. */
static unsigned int find_sec(const struct load_info *info, const char *name)
{
    unsigned int i;

    for (i = 1; i < info->hdr->e_shnum; i++) {
        Elf_Shdr *shdr = &info->sechdrs[i];
        /* Alloc bit cleared means "ignore it." */
        if ((shdr->sh_flags & SHF_ALLOC)
            && strcmp(info->secstrings + shdr->sh_name, name) == 0)
            return i;
    }
    return 0;
}

/* Find a module section, or NULL. */
static void *section_addr(const struct load_info *info, const char *name)
{
    /* Section 0 has sh_addr 0. */
    return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
}

/* Find a module section, or NULL.  Fill in number of "objects" in section. */
static void *section_objs(const struct load_info *info,
              const char *name,
              size_t object_size,
              unsigned int *num)
{
    unsigned int sec = find_sec(info, name);

    /* Section 0 has sh_addr 0 and sh_size 0. */
    *num = info->sechdrs[sec].sh_size / object_size;
    return (void *)info->sechdrs[sec].sh_addr;
}

/* Provided by the linker */
extern const struct kernel_symbol __start___ksymtab[];
extern const struct kernel_symbol __stop___ksymtab[];
extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
extern const struct kernel_symbol __start___ksymtab_gpl_future[];
extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
extern const unsigned long __start___kcrctab[];
extern const unsigned long __start___kcrctab_gpl[];
extern const unsigned long __start___kcrctab_gpl_future[];
#ifdef CONFIG_UNUSED_SYMBOLS
extern const struct kernel_symbol __start___ksymtab_unused[];
extern const struct kernel_symbol __stop___ksymtab_unused[];
extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
extern const unsigned long __start___kcrctab_unused[];
extern const unsigned long __start___kcrctab_unused_gpl[];
#endif

#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
#else
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
#endif

static bool each_symbol_in_section(const struct symsearch *arr,
                   unsigned int arrsize,
                   struct module *owner,
                   bool (*fn)(const struct symsearch *syms,
                          struct module *owner,
                          void *data),
                   void *data)
{
    unsigned int j;

    for (j = 0; j < arrsize; j++) {
        if (fn(&arr[j], owner, data))
            return true;
    }

    return false;
}

/* Returns true as soon as fn returns true, otherwise false. */
bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
                    struct module *owner,
                    void *data),
             void *data)
{
    struct module *mod;
    static const struct symsearch arr[] = {
        { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
          NOT_GPL_ONLY, false },
        { __start___ksymtab_gpl, __stop___ksymtab_gpl,
          __start___kcrctab_gpl,
          GPL_ONLY, false },
        { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
          __start___kcrctab_gpl_future,
          WILL_BE_GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
        { __start___ksymtab_unused, __stop___ksymtab_unused,
          __start___kcrctab_unused,
          NOT_GPL_ONLY, true },
        { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
          __start___kcrctab_unused_gpl,
          GPL_ONLY, true },
#endif
    };

    if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
        return true;

    list_for_each_entry_rcu(mod, &modules, list) {
        struct symsearch arr[] = {
            { mod->syms, mod->syms + mod->num_syms, mod->crcs,
              NOT_GPL_ONLY, false },
            { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
              mod->gpl_crcs,
              GPL_ONLY, false },
            { mod->gpl_future_syms,
              mod->gpl_future_syms + mod->num_gpl_future_syms,
              mod->gpl_future_crcs,
              WILL_BE_GPL_ONLY, false },
#ifdef CONFIG_UNUSED_SYMBOLS
            { mod->unused_syms,
              mod->unused_syms + mod->num_unused_syms,
              mod->unused_crcs,
              NOT_GPL_ONLY, true },
            { mod->unused_gpl_syms,
              mod->unused_gpl_syms + mod->num_unused_gpl_syms,
              mod->unused_gpl_crcs,
              GPL_ONLY, true },
#endif
        };

        if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
            return true;
    }
    return false;
}
EXPORT_SYMBOL_GPL(each_symbol_section);

struct find_symbol_arg {
    /* Input */
    const char *name;
    bool gplok;
    bool warn;

    /* Output */
    struct module *owner;
    const unsigned long *crc;
    const struct kernel_symbol *sym;
};

static bool check_symbol(const struct symsearch *syms,
                 struct module *owner,
                 unsigned int symnum, void *data)
{
    struct find_symbol_arg *fsa = data;

    if (!fsa->gplok) {
        if (syms->licence == GPL_ONLY)
            return false;
        if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
            printk(KERN_WARNING "Symbol %s is being used "
                   "by a non-GPL module, which will not "
                   "be allowed in the future\n", fsa->name);
            printk(KERN_WARNING "Please see the file "
                   "Documentation/feature-removal-schedule.txt "
                   "in the kernel source tree for more details.\n");
        }
    }

#ifdef CONFIG_UNUSED_SYMBOLS
    if (syms->unused && fsa->warn) {
        printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
               "however this module is using it.\n", fsa->name);
        printk(KERN_WARNING
               "This symbol will go away in the future.\n");
        printk(KERN_WARNING
               "Please evalute if this is the right api to use and if "
               "it really is, submit a report the linux kernel "
               "mailinglist together with submitting your code for "
               "inclusion.\n");
    }
#endif

    fsa->owner = owner;
    fsa->crc = symversion(syms->crcs, symnum);
    fsa->sym = &syms->start[symnum];
    return true;
}

static int cmp_name(const void *va, const void *vb)
{
    const char *a;
    const struct kernel_symbol *b;
    a = va; b = vb;
    return strcmp(a, b->name);
}

static bool find_symbol_in_section(const struct symsearch *syms,
                   struct module *owner,
                   void *data)
{
    struct find_symbol_arg *fsa = data;
    struct kernel_symbol *sym;

    sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
            sizeof(struct kernel_symbol), cmp_name);

    if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
        return true;

    return false;
}

/* Find a symbol and return it, along with, (optional) crc and
 * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
const struct kernel_symbol *find_symbol(const char *name,
                    struct module **owner,
                    const unsigned long **crc,
                    bool gplok,
                    bool warn)
{
    struct find_symbol_arg fsa;

    fsa.name = name;
    fsa.gplok = gplok;
    fsa.warn = warn;

    if (each_symbol_section(find_symbol_in_section, &fsa)) {
        if (owner)
            *owner = fsa.owner;
        if (crc)
            *crc = fsa.crc;
        return fsa.sym;
    }

    pr_debug("Failed to find symbol %s\n", name);
    return NULL;
}
EXPORT_SYMBOL_GPL(find_symbol);

/* Search for module by name: must hold module_mutex. */
struct module *find_module(const char *name)
{
    struct module *mod;

    list_for_each_entry(mod, &modules, list) {
        if (strcmp(mod->name, name) == 0)
            return mod;
    }
    return NULL;
}
EXPORT_SYMBOL_GPL(find_module);

#ifdef CONFIG_SMP

static inline void __percpu *mod_percpu(struct module *mod)
{
    return mod->percpu;
}

static int percpu_modalloc(struct module *mod,
               unsigned long size, unsigned long align)
{
    if (align > PAGE_SIZE) {
        printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
               mod->name, align, PAGE_SIZE);
        align = PAGE_SIZE;
    }

    mod->percpu = __alloc_reserved_percpu(size, align);
    if (!mod->percpu) {
        printk(KERN_WARNING
               "%s: Could not allocate %lu bytes percpu data\n",
               mod->name, size);
        return -ENOMEM;
    }
    mod->percpu_size = size;
    return 0;
}

static void percpu_modfree(struct module *mod)
{
    free_percpu(mod->percpu);
}

static unsigned int find_pcpusec(struct load_info *info)
{
    return find_sec(info, ".data..percpu");
}

static void percpu_modcopy(struct module *mod,
               const void *from, unsigned long size)
{
    int cpu;

    for_each_possible_cpu(cpu)
        memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
}

bool is_module_percpu_address(unsigned long addr)
{
    struct module *mod;
    unsigned int cpu;

    preempt_disable();

    list_for_each_entry_rcu(mod, &modules, list) {
        if (!mod->percpu_size)
            continue;
        for_each_possible_cpu(cpu) {
            void *start = per_cpu_ptr(mod->percpu, cpu);

            if ((void *)addr >= start &&
                (void *)addr < start + mod->percpu_size) {
                preempt_enable();
                return true;
            }
        }
    }

    preempt_enable();
    return false;
}

#else /* ... !CONFIG_SMP */

static inline void __percpu *mod_percpu(struct module *mod)
{
    return NULL;
}
static inline int percpu_modalloc(struct module *mod,
                  unsigned long size, unsigned long align)
{
    return -ENOMEM;
}
static inline void percpu_modfree(struct module *mod)
{
}
static unsigned int find_pcpusec(struct load_info *info)
{
    return 0;
}
static inline void percpu_modcopy(struct module *mod,
                  const void *from, unsigned long size)
{
    /* pcpusec should be 0, and size of that section should be 0. */
    BUG_ON(size != 0);
}
bool is_module_percpu_address(unsigned long addr)
{
    return false;
}

#endif /* CONFIG_SMP */

#define MODINFO_ATTR(field) \
static void setup_modinfo_##field(struct module *mod, const char *s)  \
{                                                                     \
    mod->field = kstrdup(s, GFP_KERNEL);                          \
}                                                                     \
static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
            struct module_kobject *mk, char *buffer)      \
{                                                                     \
    return sprintf(buffer, "%s\n", mk->mod->field);               \
}                                                                     \
static int modinfo_##field##_exists(struct module *mod)               \
{                                                                     \
    return mod->field != NULL;                                    \
}                                                                     \
static void free_modinfo_##field(struct module *mod)                  \
{                                                                     \
    kfree(mod->field);                                            \
    mod->field = NULL;                                            \
}                                                                     \
static struct module_attribute modinfo_##field = {                    \
    .attr = { .name = __stringify(field), .mode = 0444 },         \
    .show = show_modinfo_##field,                                 \
    .setup = setup_modinfo_##field,                               \
    .test = modinfo_##field##_exists,                             \
    .free = free_modinfo_##field,                                 \
};

MODINFO_ATTR(version);
MODINFO_ATTR(srcversion);

static char last_unloaded_module[MODULE_NAME_LEN+1];

#ifdef CONFIG_MODULE_UNLOAD

EXPORT_TRACEPOINT_SYMBOL(module_get);

/* Init the unload section of the module. */
static int module_unload_init(struct module *mod)
{
    mod->refptr = alloc_percpu(struct module_ref);
    if (!mod->refptr)
        return -ENOMEM;

    INIT_LIST_HEAD(&mod->source_list);
    INIT_LIST_HEAD(&mod->target_list);

    /* Hold reference count during initialization. */
    __this_cpu_write(mod->refptr->incs, 1);
    /* Backwards compatibility macros put refcount during init. */
    mod->waiter = current;

    return 0;
}

/* Does a already use b? */
static int already_uses(struct module *a, struct module *b)
{
    struct module_use *use;

    list_for_each_entry(use, &b->source_list, source_list) {
        if (use->source == a) {
            pr_debug("%s uses %s!\n", a->name, b->name);
            return 1;
        }
    }
    pr_debug("%s does not use %s!\n", a->name, b->name);
    return 0;
}

/*
 * Module a uses b
 *  - we add 'a' as a "source", 'b' as a "target" of module use
 *  - the module_use is added to the list of 'b' sources (so
 *    'b' can walk the list to see who sourced them), and of 'a'
 *    targets (so 'a' can see what modules it targets).
 */
static int add_module_usage(struct module *a, struct module *b)
{
    struct module_use *use;

    pr_debug("Allocating new usage for %s.\n", a->name);
    use = kmalloc(sizeof(*use), GFP_ATOMIC);
    if (!use) {
        printk(KERN_WARNING "%s: out of memory loading\n", a->name);
        return -ENOMEM;
    }

    use->source = a;
    use->target = b;
    list_add(&use->source_list, &b->source_list);
    list_add(&use->target_list, &a->target_list);
    return 0;
}

/* Module a uses b: caller needs module_mutex() */
int ref_module(struct module *a, struct module *b)
{
    int err;

    if (b == NULL || already_uses(a, b))
        return 0;

    /* If module isn't available, we fail. */
    err = strong_try_module_get(b);
    if (err)
        return err;

    err = add_module_usage(a, b);
    if (err) {
        module_put(b);
        return err;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(ref_module);

/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
    struct module_use *use, *tmp;

    mutex_lock(&module_mutex);
    list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
        struct module *i = use->target;
        pr_debug("%s unusing %s\n", mod->name, i->name);
        module_put(i);
        list_del(&use->source_list);
        list_del(&use->target_list);
        kfree(use);
    }
    mutex_unlock(&module_mutex);

    free_percpu(mod->refptr);
}

#ifdef CONFIG_MODULE_FORCE_UNLOAD
static inline int try_force_unload(unsigned int flags)
{
    int ret = (flags & O_TRUNC);
    if (ret)
        add_taint(TAINT_FORCED_RMMOD);
    return ret;
}
#else
static inline int try_force_unload(unsigned int flags)
{
    return 0;
}
#endif /* CONFIG_MODULE_FORCE_UNLOAD */

struct stopref
{
    struct module *mod;
    int flags;
    int *forced;
};

/* Whole machine is stopped with interrupts off when this runs. */
static int __try_stop_module(void *_sref)
{
    struct stopref *sref = _sref;

    /* If it's not unused, quit unless we're forcing. */
    if (module_refcount(sref->mod) != 0) {
        if (!(*sref->forced = try_force_unload(sref->flags)))
            return -EWOULDBLOCK;
    }

    /* Mark it as dying. */
    sref->mod->state = MODULE_STATE_GOING;
    return 0;
}

static int try_stop_module(struct module *mod, int flags, int *forced)
{
    if (flags & O_NONBLOCK) {
        struct stopref sref = { mod, flags, forced };

        return stop_machine(__try_stop_module, &sref, NULL);
    } else {
        /* We don't need to stop the machine for this. */
        mod->state = MODULE_STATE_GOING;
        synchronize_sched();
        return 0;
    }
}

unsigned long module_refcount(struct module *mod)
{
    unsigned long incs = 0, decs = 0;
    int cpu;

    for_each_possible_cpu(cpu)
        decs += per_cpu_ptr(mod->refptr, cpu)->decs;
    /*
     * ensure the incs are added up after the decs.
     * module_put ensures incs are visible before decs with smp_wmb.
     *
     * This 2-count scheme avoids the situation where the refcount
     * for CPU0 is read, then CPU0 increments the module refcount,
     * then CPU1 drops that refcount, then the refcount for CPU1 is
     * read. We would record a decrement but not its corresponding
     * increment so we would see a low count (disaster).
     *
     * Rare situation? But module_refcount can be preempted, and we
     * might be tallying up 4096+ CPUs. So it is not impossible.
     */
    smp_rmb();
    for_each_possible_cpu(cpu)
        incs += per_cpu_ptr(mod->refptr, cpu)->incs;
    return incs - decs;
}
EXPORT_SYMBOL(module_refcount);

/* This exists whether we can unload or not */
static void free_module(struct module *mod);

static void wait_for_zero_refcount(struct module *mod)
{
    /* Since we might sleep for some time, release the mutex first */
    mutex_unlock(&module_mutex);
    for (;;) {
        pr_debug("Looking at refcount...\n");
        set_current_state(TASK_UNINTERRUPTIBLE);
        if (module_refcount(mod) == 0)
            break;
        schedule();
    }
    current->state = TASK_RUNNING;
    mutex_lock(&module_mutex);
}

SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
        unsigned int, flags)
{
    struct module *mod;
    char name[MODULE_NAME_LEN];
    int ret, forced = 0;

    if (!capable(CAP_SYS_MODULE) || modules_disabled)
        return -EPERM;

    if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
        return -EFAULT;
    name[MODULE_NAME_LEN-1] = '\0';

    if (mutex_lock_interruptible(&module_mutex) != 0)
        return -EINTR;

    mod = find_module(name);
    if (!mod) {
        ret = -ENOENT;
        goto out;
    }

    if (!list_empty(&mod->source_list)) {
        /* Other modules depend on us: get rid of them first. */
        ret = -EWOULDBLOCK;
        goto out;
    }

    /* Doing init or already dying? */
    if (mod->state != MODULE_STATE_LIVE) {
        /* FIXME: if (force), slam module count and wake up
                   waiter --RR */
        pr_debug("%s already dying\n", mod->name);
        ret = -EBUSY;
        goto out;
    }

    /* If it has an init func, it must have an exit func to unload */
    if (mod->init && !mod->exit) {
        forced = try_force_unload(flags);
        if (!forced) {
            /* This module can't be removed */
            ret = -EBUSY;
            goto out;
        }
    }

    /* Set this up before setting mod->state */
    mod->waiter = current;

    /* Stop the machine so refcounts can't move and disable module. */
    ret = try_stop_module(mod, flags, &forced);
    if (ret != 0)
        goto out;

    /* Never wait if forced. */
    if (!forced && module_refcount(mod) != 0)
        wait_for_zero_refcount(mod);

    mutex_unlock(&module_mutex);
    /* Final destruction now no one is using it. */
    if (mod->exit != NULL)
        mod->exit();
    blocking_notifier_call_chain(&module_notify_list,
                     MODULE_STATE_GOING, mod);
    async_synchronize_full();

    /* Store the name of the last unloaded module for diagnostic purposes */
    strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));

    free_module(mod);
    return 0;
out:
    mutex_unlock(&module_mutex);
    return ret;
}

static inline void print_unload_info(struct seq_file *m, struct module *mod)
{
    struct module_use *use;
    int printed_something = 0;

    seq_printf(m, " %lu ", module_refcount(mod));

    /* Always include a trailing , so userspace can differentiate
           between this and the old multi-field proc format. */
    list_for_each_entry(use, &mod->source_list, source_list) {
        printed_something = 1;
        seq_printf(m, "%s,", use->source->name);
    }

    if (mod->init != NULL && mod->exit == NULL) {
        printed_something = 1;
        seq_printf(m, "[permanent],");
    }

    if (!printed_something)
        seq_printf(m, "-");
}

void __symbol_put(const char *symbol)
{
    struct module *owner;

    preempt_disable();
    if (!find_symbol(symbol, &owner, NULL, true, false))
        BUG();
    module_put(owner);
    preempt_enable();
}
EXPORT_SYMBOL(__symbol_put);

/* Note this assumes addr is a function, which it currently always is. */
void symbol_put_addr(void *addr)
{
    struct module *modaddr;
    unsigned long a = (unsigned long)dereference_function_descriptor(addr);

    if (core_kernel_text(a))
        return;

    /* module_text_address is safe here: we're supposed to have reference
     * to module from symbol_get, so it can't go away. */
    modaddr = __module_text_address(a);
    BUG_ON(!modaddr);
    module_put(modaddr);
}
EXPORT_SYMBOL_GPL(symbol_put_addr);

static ssize_t show_refcnt(struct module_attribute *mattr,
               struct module_kobject *mk, char *buffer)
{
    return sprintf(buffer, "%lu\n", module_refcount(mk->mod));
}

static struct module_attribute modinfo_refcnt =
    __ATTR(refcnt, 0444, show_refcnt, NULL);

void __module_get(struct module *module)
{
    if (module) {
        preempt_disable();
        __this_cpu_inc(module->refptr->incs);
        trace_module_get(module, _RET_IP_);
        preempt_enable();
    }
}
EXPORT_SYMBOL(__module_get);

bool try_module_get(struct module *module)
{
    bool ret = true;

    if (module) {
        preempt_disable();

        if (likely(module_is_live(module))) {
            __this_cpu_inc(module->refptr->incs);
            trace_module_get(module, _RET_IP_);
        } else
            ret = false;

        preempt_enable();
    }
    return ret;
}
EXPORT_SYMBOL(try_module_get);

void module_put(struct module *module)
{
    if (module) {
        preempt_disable();
        smp_wmb(); /* see comment in module_refcount */
        __this_cpu_inc(module->refptr->decs);

        trace_module_put(module, _RET_IP_);
        /* Maybe they're waiting for us to drop reference? */
        if (unlikely(!module_is_live(module)))
            wake_up_process(module->waiter);
        preempt_enable();
    }
}
EXPORT_SYMBOL(module_put);

#else /* !CONFIG_MODULE_UNLOAD */
static inline void print_unload_info(struct seq_file *m, struct module *mod)
{
    /* We don't know the usage count, or what modules are using. */
    seq_printf(m, " - -");
}

static inline void module_unload_free(struct module *mod)
{
}

int ref_module(struct module *a, struct module *b)
{
    return strong_try_module_get(b);
}
EXPORT_SYMBOL_GPL(ref_module);

static inline int module_unload_init(struct module *mod)
{
    return 0;
}
#endif /* CONFIG_MODULE_UNLOAD */

static size_t module_flags_taint(struct module *mod, char *buf)
{
    size_t l = 0;

    if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
        buf[l++] = 'P';
    if (mod->taints & (1 << TAINT_OOT_MODULE))
        buf[l++] = 'O';
    if (mod->taints & (1 << TAINT_FORCED_MODULE))
        buf[l++] = 'F';
    if (mod->taints & (1 << TAINT_CRAP))
        buf[l++] = 'C';
    /*
     * TAINT_FORCED_RMMOD: could be added.
     * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
     * apply to modules.
     */
    return l;
}

static ssize_t show_initstate(struct module_attribute *mattr,
                  struct module_kobject *mk, char *buffer)
{
    const char *state = "unknown";

    switch (mk->mod->state) {
    case MODULE_STATE_LIVE:
        state = "live";
        break;
    case MODULE_STATE_COMING:
        state = "coming";
        break;
    case MODULE_STATE_GOING:
        state = "going";
        break;
    }
    return sprintf(buffer, "%s\n", state);
}

static struct module_attribute modinfo_initstate =
    __ATTR(initstate, 0444, show_initstate, NULL);

static ssize_t store_uevent(struct module_attribute *mattr,
                struct module_kobject *mk,
                const char *buffer, size_t count)
{
    enum kobject_action action;

    if (kobject_action_type(buffer, count, &action) == 0)
        kobject_uevent(&mk->kobj, action);
    return count;
}

struct module_attribute module_uevent =
    __ATTR(uevent, 0200, NULL, store_uevent);

static ssize_t show_coresize(struct module_attribute *mattr,
                 struct module_kobject *mk, char *buffer)
{
    return sprintf(buffer, "%u\n", mk->mod->core_size);
}

static struct module_attribute modinfo_coresize =
    __ATTR(coresize, 0444, show_coresize, NULL);

static ssize_t show_initsize(struct module_attribute *mattr,
                 struct module_kobject *mk, char *buffer)
{
    return sprintf(buffer, "%u\n", mk->mod->init_size);
}

static struct module_attribute modinfo_initsize =
    __ATTR(initsize, 0444, show_initsize, NULL);

static ssize_t show_taint(struct module_attribute *mattr,
              struct module_kobject *mk, char *buffer)
{
    size_t l;

    l = module_flags_taint(mk->mod, buffer);
    buffer[l++] = '\n';
    return l;
}

static struct module_attribute modinfo_taint =
    __ATTR(taint, 0444, show_taint, NULL);

static struct module_attribute *modinfo_attrs[] = {
    &module_uevent,
    &modinfo_version,
    &modinfo_srcversion,
    &modinfo_initstate,
    &modinfo_coresize,
    &modinfo_initsize,
    &modinfo_taint,
#ifdef CONFIG_MODULE_UNLOAD
    &modinfo_refcnt,
#endif
    NULL,
};

static const char vermagic[] = VERMAGIC_STRING;

static int try_to_force_load(struct module *mod, const char *reason)
{
#ifdef CONFIG_MODULE_FORCE_LOAD
    if (!test_taint(TAINT_FORCED_MODULE))
        printk(KERN_WARNING "%s: %s: kernel tainted.\n",
               mod->name, reason);
    add_taint_module(mod, TAINT_FORCED_MODULE);
    return 0;
#else
    return -ENOEXEC;
#endif
}

#ifdef CONFIG_MODVERSIONS
/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
static unsigned long maybe_relocated(unsigned long crc,
                     const struct module *crc_owner)
{
#ifdef ARCH_RELOCATES_KCRCTAB
    if (crc_owner == NULL)
        return crc - (unsigned long)reloc_start;
#endif
    return crc;
}

static int check_version(Elf_Shdr *sechdrs,
             unsigned int versindex,
             const char *symname,
             struct module *mod, 
             const unsigned long *crc,
             const struct module *crc_owner)
{
    unsigned int i, num_versions;
    struct modversion_info *versions;

    /* Exporting module didn't supply crcs?  OK, we're already tainted. */
    if (!crc)
        return 1;

    /* No versions at all?  modprobe --force does this. */
    if (versindex == 0)
        return try_to_force_load(mod, symname) == 0;

    versions = (void *) sechdrs[versindex].sh_addr;
    num_versions = sechdrs[versindex].sh_size
        / sizeof(struct modversion_info);

    for (i = 0; i < num_versions; i++) {
        if (strcmp(versions[i].name, symname) != 0)
            continue;

        if (versions[i].crc == maybe_relocated(*crc, crc_owner))
            return 1;
        pr_debug("Found checksum %lX vs module %lX\n",
               maybe_relocated(*crc, crc_owner), versions[i].crc);
        goto bad_version;
    }

    printk(KERN_WARNING "%s: no symbol version for %s\n",
           mod->name, symname);
    return 0;

bad_version:
    printk("%s: disagrees about version of symbol %s\n",
           mod->name, symname);
    return 0;
}

static inline int check_modstruct_version(Elf_Shdr *sechdrs,
                      unsigned int versindex,
                      struct module *mod)
{
    const unsigned long *crc;

    /* Since this should be found in kernel (which can't be removed),
     * no locking is necessary. */
    if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
             &crc, true, false))
        BUG();
    return check_version(sechdrs, versindex, "module_layout", mod, crc,
                 NULL);
}

/* First part is kernel version, which we ignore if module has crcs. */
static inline int same_magic(const char *amagic, const char *bmagic,
                 bool has_crcs)
{
    if (has_crcs) {
        amagic += strcspn(amagic, " ");
        bmagic += strcspn(bmagic, " ");
    }
    return strcmp(amagic, bmagic) == 0;
}
#else
static inline int check_version(Elf_Shdr *sechdrs,
                unsigned int versindex,
                const char *symname,
                struct module *mod, 
                const unsigned long *crc,
                const struct module *crc_owner)
{
    return 1;
}

static inline int check_modstruct_version(Elf_Shdr *sechdrs,
                      unsigned int versindex,
                      struct module *mod)
{
    return 1;
}

static inline int same_magic(const char *amagic, const char *bmagic,
                 bool has_crcs)
{
    return strcmp(amagic, bmagic) == 0;
}
#endif /* CONFIG_MODVERSIONS */

/* Resolve a symbol for this module.  I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(struct module *mod,
                          const struct load_info *info,
                          const char *name,
                          char ownername[])
{
    struct module *owner;
    const struct kernel_symbol *sym;
    const unsigned long *crc;
    int err;

    mutex_lock(&module_mutex);
    sym = find_symbol(name, &owner, &crc,
              !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
    if (!sym)
        goto unlock;

    if (!check_version(info->sechdrs, info->index.vers, name, mod, crc,
               owner)) {
        sym = ERR_PTR(-EINVAL);
        goto getname;
    }

    err = ref_module(mod, owner);
    if (err) {
        sym = ERR_PTR(err);
        goto getname;
    }

getname:
    /* We must make copy under the lock if we failed to get ref. */
    strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
unlock:
    mutex_unlock(&module_mutex);
    return sym;
}

static const struct kernel_symbol *
resolve_symbol_wait(struct module *mod,
            const struct load_info *info,
            const char *name)
{
    const struct kernel_symbol *ksym;
    char owner[MODULE_NAME_LEN];

    if (wait_event_interruptible_timeout(module_wq,
            !IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
            || PTR_ERR(ksym) != -EBUSY,
                         30 * HZ) <= 0) {
        printk(KERN_WARNING "%s: gave up waiting for init of module %s.\n",
               mod->name, owner);
    }
    return ksym;
}

/*
 * /sys/module/foo/sections stuff
 * J. Corbet <[email protected]>
 */
#ifdef CONFIG_SYSFS

#ifdef CONFIG_KALLSYMS
static inline bool sect_empty(const Elf_Shdr *sect)
{
    return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
}

struct module_sect_attr
{
    struct module_attribute mattr;
    char *name;
    unsigned long address;
};

struct module_sect_attrs
{
    struct attribute_group grp;
    unsigned int nsections;
    struct module_sect_attr attrs[0];
};

static ssize_t module_sect_show(struct module_attribute *mattr,
                struct module_kobject *mk, char *buf)
{
    struct module_sect_attr *sattr =
        container_of(mattr, struct module_sect_attr, mattr);
    return sprintf(buf, "0x%pK\n", (void *)sattr->address);
}

static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
{
    unsigned int section;

    for (section = 0; section < sect_attrs->nsections; section++)
        kfree(sect_attrs->attrs[section].name);
    kfree(sect_attrs);
}

static void add_sect_attrs(struct module *mod, const struct load_info *info)
{
    unsigned int nloaded = 0, i, size[2];
    struct module_sect_attrs *sect_attrs;
    struct module_sect_attr *sattr;
    struct attribute **gattr;

    /* Count loaded sections and allocate structures */
    for (i = 0; i < info->hdr->e_shnum; i++)
        if (!sect_empty(&info->sechdrs[i]))
            nloaded++;
    size[0] = ALIGN(sizeof(*sect_attrs)
            + nloaded * sizeof(sect_attrs->attrs[0]),
            sizeof(sect_attrs->grp.attrs[0]));
    size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]);
    sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
    if (sect_attrs == NULL)
        return;

    /* Setup section attributes. */
    sect_attrs->grp.name = "sections";
    sect_attrs->grp.attrs = (void *)sect_attrs + size[0];

    sect_attrs->nsections = 0;
    sattr = &sect_attrs->attrs[0];
    gattr = &sect_attrs->grp.attrs[0];
    for (i = 0; i < info->hdr->e_shnum; i++) {
        Elf_Shdr *sec = &info->sechdrs[i];
        if (sect_empty(sec))
            continue;
        sattr->address = sec->sh_addr;
        sattr->name = kstrdup(info->secstrings + sec->sh_name,
                    GFP_KERNEL);
        if (sattr->name == NULL)
            goto out;
        sect_attrs->nsections++;
        sysfs_attr_init(&sattr->mattr.attr);
        sattr->mattr.show = module_sect_show;
        sattr->mattr.store = NULL;
        sattr->mattr.attr.name = sattr->name;
        sattr->mattr.attr.mode = S_IRUGO;
        *(gattr++) = &(sattr++)->mattr.attr;
    }
    *gattr = NULL;

    if (sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp))
        goto out;

    mod->sect_attrs = sect_attrs;
    return;
  out:
    free_sect_attrs(sect_attrs);
}

static void remove_sect_attrs(struct module *mod)
{
    if (mod->sect_attrs) {
        sysfs_remove_group(&mod->mkobj.kobj,
                   &mod->sect_attrs->grp);
        /* We are positive that no one is using any sect attrs
         * at this point.  Deallocate immediately. */
        free_sect_attrs(mod->sect_attrs);
        mod->sect_attrs = NULL;
    }
}

/*
 * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
 */

struct module_notes_attrs {
    struct kobject *dir;
    unsigned int notes;
    struct bin_attribute attrs[0];
};

static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
                 struct bin_attribute *bin_attr,
                 char *buf, loff_t pos, size_t count)
{
    /*
     * The caller checked the pos and count against our size.
     */
    memcpy(buf, bin_attr->private + pos, count);
    return count;
}

static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
                 unsigned int i)
{
    if (notes_attrs->dir) {
        while (i-- > 0)
            sysfs_remove_bin_file(notes_attrs->dir,
                          &notes_attrs->attrs[i]);
        kobject_put(notes_attrs->dir);
    }
    kfree(notes_attrs);
}

static void add_notes_attrs(struct module *mod, const struct load_info *info)
{
    unsigned int notes, loaded, i;
    struct module_notes_attrs *notes_attrs;
    struct bin_attribute *nattr;

    /* failed to create section attributes, so can't create notes */
    if (!mod->sect_attrs)
        return;

    /* Count notes sections and allocate structures.  */
    notes = 0;
    for (i = 0; i < info->hdr->e_shnum; i++)
        if (!sect_empty(&info->sechdrs[i]) &&
            (info->sechdrs[i].sh_type == SHT_NOTE))
            ++notes;

    if (notes == 0)
        return;

    notes_attrs = kzalloc(sizeof(*notes_attrs)
                  + notes * sizeof(notes_attrs->attrs[0]),
                  GFP_KERNEL);
    if (notes_attrs == NULL)
        return;

    notes_attrs->notes = notes;
    nattr = &notes_attrs->attrs[0];
    for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {
        if (sect_empty(&info->sechdrs[i]))
            continue;
        if (info->sechdrs[i].sh_type == SHT_NOTE) {
            sysfs_bin_attr_init(nattr);
            nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
            nattr->attr.mode = S_IRUGO;
            nattr->size = info->sechdrs[i].sh_size;
            nattr->private = (void *) info->sechdrs[i].sh_addr;
            nattr->read = module_notes_read;
            ++nattr;
        }
        ++loaded;
    }

    notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
    if (!notes_attrs->dir)
        goto out;

    for (i = 0; i < notes; ++i)
        if (sysfs_create_bin_file(notes_attrs->dir,
                      &notes_attrs->attrs[i]))
            goto out;

    mod->notes_attrs = notes_attrs;
    return;

  out:
    free_notes_attrs(notes_attrs, i);
}

static void remove_notes_attrs(struct module *mod)
{
    if (mod->notes_attrs)
        free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
}

#else

static inline void add_sect_attrs(struct module *mod,
                  const struct load_info *info)
{
}

static inline void remove_sect_attrs(struct module *mod)
{
}

static inline void add_notes_attrs(struct module *mod,
                   const struct load_info *info)
{
}

static inline void remove_notes_attrs(struct module *mod)
{
}
#endif /* CONFIG_KALLSYMS */

static void add_usage_links(struct module *mod)
{
#ifdef CONFIG_MODULE_UNLOAD
    struct module_use *use;
    int nowarn;

    mutex_lock(&module_mutex);
    list_for_each_entry(use, &mod->target_list, target_list) {
        nowarn = sysfs_create_link(use->target->holders_dir,
                       &mod->mkobj.kobj, mod->name);
    }
    mutex_unlock(&module_mutex);
#endif
}

static void del_usage_links(struct module *mod)
{
#ifdef CONFIG_MODULE_UNLOAD
    struct module_use *use;

    mutex_lock(&module_mutex);
    list_for_each_entry(use, &mod->target_list, target_list)
        sysfs_remove_link(use->target->holders_dir, mod->name);
    mutex_unlock(&module_mutex);
#endif
}

static int module_add_modinfo_attrs(struct module *mod)
{
    struct module_attribute *attr;
    struct module_attribute *temp_attr;
    int error = 0;
    int i;

    mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
                    (ARRAY_SIZE(modinfo_attrs) + 1)),
                    GFP_KERNEL);
    if (!mod->modinfo_attrs)
        return -ENOMEM;

    temp_attr = mod->modinfo_attrs;
    for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
        if (!attr->test ||
            (attr->test && attr->test(mod))) {
            memcpy(temp_attr, attr, sizeof(*temp_attr));
            sysfs_attr_init(&temp_attr->attr);
            error = sysfs_create_file(&mod->mkobj.kobj,&temp_attr->attr);
            ++temp_attr;
        }
    }
    return error;
}

static void module_remove_modinfo_attrs(struct module *mod)
{
    struct module_attribute *attr;
    int i;

    for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
        /* pick a field to test for end of list */
        if (!attr->attr.name)
            break;
        sysfs_remove_file(&mod->mkobj.kobj,&attr->attr);
        if (attr->free)
            attr->free(mod);
    }
    kfree(mod->modinfo_attrs);
}

static int mod_sysfs_init(struct module *mod)
{
    int err;
    struct kobject *kobj;

    if (!module_sysfs_initialized) {
        printk(KERN_ERR "%s: module sysfs not initialized\n",
               mod->name);
        err = -EINVAL;
        goto out;
    }

    kobj = kset_find_obj(module_kset, mod->name);
    if (kobj) {
        printk(KERN_ERR "%s: module is already loaded\n", mod->name);
        kobject_put(kobj);
        err = -EINVAL;
        goto out;
    }

    mod->mkobj.mod = mod;

    memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
    mod->mkobj.kobj.kset = module_kset;
    err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
                   "%s", mod->name);
    if (err)
        kobject_put(&mod->mkobj.kobj);

    /* delay uevent until full sysfs population */
out:
    return err;
}

static int mod_sysfs_setup(struct module *mod,
               const struct load_info *info,
               struct kernel_param *kparam,
               unsigned int num_params)
{
    int err;

    err = mod_sysfs_init(mod);
    if (err)
        goto out;

    mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
    if (!mod->holders_dir) {
        err = -ENOMEM;
        goto out_unreg;
    }

    err = module_param_sysfs_setup(mod, kparam, num_params);
    if (err)
        goto out_unreg_holders;

    err = module_add_modinfo_attrs(mod);
    if (err)
        goto out_unreg_param;

    add_usage_links(mod);
    add_sect_attrs(mod, info);
    add_notes_attrs(mod, info);

    kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
    return 0;

out_unreg_param:
    module_param_sysfs_remove(mod);
out_unreg_holders:
    kobject_put(mod->holders_dir);
out_unreg:
    kobject_put(&mod->mkobj.kobj);
out:
    return err;
}

static void mod_sysfs_fini(struct module *mod)
{
    remove_notes_attrs(mod);
    remove_sect_attrs(mod);
    kobject_put(&mod->mkobj.kobj);
}

#else /* !CONFIG_SYSFS */

static int mod_sysfs_setup(struct module *mod,
               const struct load_info *info,
               struct kernel_param *kparam,
               unsigned int num_params)
{
    return 0;
}

static void mod_sysfs_fini(struct module *mod)
{
}

static void module_remove_modinfo_attrs(struct module *mod)
{
}

static void del_usage_links(struct module *mod)
{
}

#endif /* CONFIG_SYSFS */

static void mod_sysfs_teardown(struct module *mod)
{
    del_usage_links(mod);
    module_remove_modinfo_attrs(mod);
    module_param_sysfs_remove(mod);
    kobject_put(mod->mkobj.drivers_dir);
    kobject_put(mod->holders_dir);
    mod_sysfs_fini(mod);
}

/*
 * unlink the module with the whole machine is stopped with interrupts off
 * - this defends against kallsyms not taking locks
 */
static int __unlink_module(void *_mod)
{
    struct module *mod = _mod;
    list_del(&mod->list);
    module_bug_cleanup(mod);
    return 0;
}

#ifdef CONFIG_DEBUG_SET_MODULE_RONX
/*
 * LKM RO/NX protection: protect module's text/ro-data
 * from modification and any data from execution.
 */
void set_page_attributes(void *start, void *end, int (*set)(unsigned long start, int num_pages))
{
    unsigned long begin_pfn = PFN_DOWN((unsigned long)start);
    unsigned long end_pfn = PFN_DOWN((unsigned long)end);

    if (end_pfn > begin_pfn)
        set(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
}

static void set_section_ro_nx(void *base,
            unsigned long text_size,
            unsigned long ro_size,
            unsigned long total_size)
{
    /* begin and end PFNs of the current subsection */
    unsigned long begin_pfn;
    unsigned long end_pfn;

    /*
     * Set RO for module text and RO-data:
     * - Always protect first page.
     * - Do not protect last partial page.
     */
    if (ro_size > 0)
        set_page_attributes(base, base + ro_size, set_memory_ro);

    /*
     * Set NX permissions for module data:
     * - Do not protect first partial page.
     * - Always protect last page.
     */
    if (total_size > text_size) {
        begin_pfn = PFN_UP((unsigned long)base + text_size);
        end_pfn = PFN_UP((unsigned long)base + total_size);
        if (end_pfn > begin_pfn)
            set_memory_nx(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
    }
}

static void unset_module_core_ro_nx(struct module *mod)
{
    set_page_attributes(mod->module_core + mod->core_text_size,
        mod->module_core + mod->core_size,
        set_memory_x);
    set_page_attributes(mod->module_core,
        mod->module_core + mod->core_ro_size,
        set_memory_rw);
}

static void unset_module_init_ro_nx(struct module *mod)
{
    set_page_attributes(mod->module_init + mod->init_text_size,
        mod->module_init + mod->init_size,
        set_memory_x);
    set_page_attributes(mod->module_init,
        mod->module_init + mod->init_ro_size,
        set_memory_rw);
}

/* Iterate through all modules and set each module's text as RW */
void set_all_modules_text_rw(void)
{
    struct module *mod;

    mutex_lock(&module_mutex);
    list_for_each_entry_rcu(mod, &modules, list) {
        if ((mod->module_core) && (mod->core_text_size)) {
            set_page_attributes(mod->module_core,
                        mod->module_core + mod->core_text_size,
                        set_memory_rw);
        }
        if ((mod->module_init) && (mod->init_text_size)) {
            set_page_attributes(mod->module_init,
                        mod->module_init + mod->init_text_size,
                        set_memory_rw);
        }
    }
    mutex_unlock(&module_mutex);
}

/* Iterate through all modules and set each module's text as RO */
void set_all_modules_text_ro(void)
{
    struct module *mod;

    mutex_lock(&module_mutex);
    list_for_each_entry_rcu(mod, &modules, list) {
        if ((mod->module_core) && (mod->core_text_size)) {
            set_page_attributes(mod->module_core,
                        mod->module_core + mod->core_text_size,
                        set_memory_ro);
        }
        if ((mod->module_init) && (mod->init_text_size)) {
            set_page_attributes(mod->module_init,
                        mod->module_init + mod->init_text_size,
                        set_memory_ro);
        }
    }
    mutex_unlock(&module_mutex);
}
#else
static inline void set_section_ro_nx(void *base, unsigned long text_size, unsigned long ro_size, unsigned long total_size) { }
static void unset_module_core_ro_nx(struct module *mod) { }
static void unset_module_init_ro_nx(struct module *mod) { }
#endif

void __weak module_free(struct module *mod, void *module_region)
{
    vfree(module_region);
}

void __weak module_arch_cleanup(struct module *mod)
{
}

/* Free a module, remove from lists, etc. */
static void free_module(struct module *mod)
{
    trace_module_free(mod);

    /* Delete from various lists */
    mutex_lock(&module_mutex);
    stop_machine(__unlink_module, mod, NULL);
    mutex_unlock(&module_mutex);
    mod_sysfs_teardown(mod);

    /* Remove dynamic debug info */
    ddebug_remove_module(mod->name);

    /* Arch-specific cleanup. */
    module_arch_cleanup(mod);

    /* Module unload stuff */
    module_unload_free(mod);

    /* Free any allocated parameters. */
    destroy_params(mod->kp, mod->num_kp);

    /* This may be NULL, but that's OK */
    unset_module_init_ro_nx(mod);
    module_free(mod, mod->module_init);
    kfree(mod->args);
    percpu_modfree(mod);

    /* Free lock-classes: */
    lockdep_free_key_range(mod->module_core, mod->core_size);

    /* Finally, free the core (containing the module structure) */
    unset_module_core_ro_nx(mod);
    module_free(mod, mod->module_core);

#ifdef CONFIG_MPU
    update_protections(current->mm);
#endif
}

void *__symbol_get(const char *symbol)
{
    struct module *owner;
    const struct kernel_symbol *sym;

    preempt_disable();
    sym = find_symbol(symbol, &owner, NULL, true, true);
    if (sym && strong_try_module_get(owner))
        sym = NULL;
    preempt_enable();

    return sym ? (void *)sym->value : NULL;
}
EXPORT_SYMBOL_GPL(__symbol_get);

/*
 * Ensure that an exported symbol [global namespace] does not already exist
 * in the kernel or in some other module's exported symbol table.
 *
 * You must hold the module_mutex.
 */
static int verify_export_symbols(struct module *mod)
{
    unsigned int i;
    struct module *owner;
    const struct kernel_symbol *s;
    struct {
        const struct kernel_symbol *sym;
        unsigned int num;
    } arr[] = {
        { mod->syms, mod->num_syms },
        { mod->gpl_syms, mod->num_gpl_syms },
        { mod->gpl_future_syms, mod->num_gpl_future_syms },
#ifdef CONFIG_UNUSED_SYMBOLS
        { mod->unused_syms, mod->num_unused_syms },
        { mod->unused_gpl_syms, mod->num_unused_gpl_syms },
#endif
    };

    for (i = 0; i < ARRAY_SIZE(arr); i++) {
        for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
            if (find_symbol(s->name, &owner, NULL, true, false)) {
                printk(KERN_ERR
                       "%s: exports duplicate symbol %s"
                       " (owned by %s)\n",
                       mod->name, s->name, module_name(owner));
                return -ENOEXEC;
            }
        }
    }
    return 0;
}

/* Change all symbols so that st_value encodes the pointer directly. */
static int simplify_symbols(struct module *mod, const struct load_info *info)
{
    Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
    Elf_Sym *sym = (void *)symsec->sh_addr;
    unsigned long secbase;
    unsigned int i;
    int ret = 0;
    const struct kernel_symbol *ksym;

    for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
        const char *name = info->strtab + sym[i].st_name;

        switch (sym[i].st_shndx) {
        case SHN_COMMON:
            /* We compiled with -fno-common.  These are not
               supposed to happen.  */
            pr_debug("Common symbol: %s\n", name);
            printk("%s: please compile with -fno-common\n",
                   mod->name);
            ret = -ENOEXEC;
            break;

        case SHN_ABS:
            /* Don't need to do anything */
            pr_debug("Absolute symbol: 0x%08lx\n",
                   (long)sym[i].st_value);
            break;

        case SHN_UNDEF:
            ksym = resolve_symbol_wait(mod, info, name);
            /* Ok if resolved.  */
            if (ksym && !IS_ERR(ksym)) {
                sym[i].st_value = ksym->value;
                break;
            }

            /* Ok if weak.  */
            if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
                break;

            printk(KERN_WARNING "%s: Unknown symbol %s (err %li)\n",
                   mod->name, name, PTR_ERR(ksym));
            ret = PTR_ERR(ksym) ?: -ENOENT;
            break;

        default:
            /* Divert to percpu allocation if a percpu var. */
            if (sym[i].st_shndx == info->index.pcpu)
                secbase = (unsigned long)mod_percpu(mod);
            else
                secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
            sym[i].st_value += secbase;
            break;
        }
    }

    return ret;
}

static int apply_relocations(struct module *mod, const struct load_info *info)
{
    unsigned int i;
    int err = 0;

    /* Now do relocations. */
    for (i = 1; i < info->hdr->e_shnum; i++) {
        unsigned int infosec = info->sechdrs[i].sh_info;

        /* Not a valid relocation section? */
        if (infosec >= info->hdr->e_shnum)
            continue;

        /* Don't bother with non-allocated sections */
        if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
            continue;

        if (info->sechdrs[i].sh_type == SHT_REL)
            err = apply_relocate(info->sechdrs, info->strtab,
                         info->index.sym, i, mod);
        else if (info->sechdrs[i].sh_type == SHT_RELA)
            err = apply_relocate_add(info->sechdrs, info->strtab,
                         info->index.sym, i, mod);
        if (err < 0)
            break;
    }
    return err;
}

/* Additional bytes needed by arch in front of individual sections */
unsigned int __weak arch_mod_section_prepend(struct module *mod,
                         unsigned int section)
{
    /* default implementation just returns zero */
    return 0;
}

/* Update size with this section: return offset. */
static long get_offset(struct module *mod, unsigned int *size,
               Elf_Shdr *sechdr, unsigned int section)
{
    long ret;

    *size += arch_mod_section_prepend(mod, section);
    ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
    *size = ret + sechdr->sh_size;
    return ret;
}

/* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
   might -- code, read-only data, read-write data, small data.  Tally
   sizes, and place the offsets into sh_entsize fields: high bit means it
   belongs in init. */
static void layout_sections(struct module *mod, struct load_info *info)
{
    static unsigned long const masks[][2] = {
        /* NOTE: all executable code must be the first section
         * in this array; otherwise modify the text_size
         * finder in the two loops below */
        { SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
        { SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
        { SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
        { ARCH_SHF_SMALL | SHF_ALLOC, 0 }
    };
    unsigned int m, i;

    for (i = 0; i < info->hdr->e_shnum; i++)
        info->sechdrs[i].sh_entsize = ~0UL;

    pr_debug("Core section allocation order:\n");
    for (m = 0; m < ARRAY_SIZE(masks); ++m) {
        for (i = 0; i < info->hdr->e_shnum; ++i) {
            Elf_Shdr *s = &info->sechdrs[i];
            const char *sname = info->secstrings + s->sh_name;

            if ((s->sh_flags & masks[m][0]) != masks[m][0]
                || (s->sh_flags & masks[m][1])
                || s->sh_entsize != ~0UL
                || strstarts(sname, ".init"))
                continue;
            s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
            pr_debug("\t%s\n", sname);
        }
        switch (m) {
        case 0: /* executable */
            mod->core_size = debug_align(mod->core_size);
            mod->core_text_size = mod->core_size;
            break;
        case 1: /* RO: text and ro-data */
            mod->core_size = debug_align(mod->core_size);
            mod->core_ro_size = mod->core_size;
            break;
        case 3: /* whole core */
            mod->core_size = debug_align(mod->core_size);
            break;
        }
    }

    pr_debug("Init section allocation order:\n");
    for (m = 0; m < ARRAY_SIZE(masks); ++m) {
        for (i = 0; i < info->hdr->e_shnum; ++i) {
            Elf_Shdr *s = &info->sechdrs[i];
            const char *sname = info->secstrings + s->sh_name;

            if ((s->sh_flags & masks[m][0]) != masks[m][0]
                || (s->sh_flags & masks[m][1])
                || s->sh_entsize != ~0UL
                || !strstarts(sname, ".init"))
                continue;
            s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
                     | INIT_OFFSET_MASK);
            pr_debug("\t%s\n", sname);
        }
        switch (m) {
        case 0: /* executable */
            mod->init_size = debug_align(mod->init_size);
            mod->init_text_size = mod->init_size;
            break;
        case 1: /* RO: text and ro-data */
            mod->init_size = debug_align(mod->init_size);
            mod->init_ro_size = mod->init_size;
            break;
        case 3: /* whole init */
            mod->init_size = debug_align(mod->init_size);
            break;
        }
    }
}

static void set_license(struct module *mod, const char *license)
{
    if (!license)
        license = "unspecified";

    if (!license_is_gpl_compatible(license)) {
        if (!test_taint(TAINT_PROPRIETARY_MODULE))
            printk(KERN_WARNING "%s: module license '%s' taints "
                "kernel.\n", mod->name, license);
        add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
    }
}

/* Parse tag=value strings from .modinfo section */
static char *next_string(char *string, unsigned long *secsize)
{
    /* Skip non-zero chars */
    while (string[0]) {
        string++;
        if ((*secsize)-- <= 1)
            return NULL;
    }

    /* Skip any zero padding. */
    while (!string[0]) {
        string++;
        if ((*secsize)-- <= 1)
            return NULL;
    }
    return string;
}

static char *get_modinfo(struct load_info *info, const char *tag)
{
    char *p;
    unsigned int taglen = strlen(tag);
    Elf_Shdr *infosec = &info->sechdrs[info->index.info];
    unsigned long size = infosec->sh_size;

    for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) {
        if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
            return p + taglen + 1;
    }
    return NULL;
}

static void setup_modinfo(struct module *mod, struct load_info *info)
{
    struct module_attribute *attr;
    int i;

    for (i = 0; (attr = modinfo_attrs[i]); i++) {
        if (attr->setup)
            attr->setup(mod, get_modinfo(info, attr->attr.name));
    }
}

static void free_modinfo(struct module *mod)
{
    struct module_attribute *attr;
    int i;

    for (i = 0; (attr = modinfo_attrs[i]); i++) {
        if (attr->free)
            attr->free(mod);
    }
}

#ifdef CONFIG_KALLSYMS

/* lookup symbol in given range of kernel_symbols */
static const struct kernel_symbol *lookup_symbol(const char *name,
    const struct kernel_symbol *start,
    const struct kernel_symbol *stop)
{
    return bsearch(name, start, stop - start,
            sizeof(struct kernel_symbol), cmp_name);
}

static int is_exported(const char *name, unsigned long value,
               const struct module *mod)
{
    const struct kernel_symbol *ks;
    if (!mod)
        ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
    else
        ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
    return ks != NULL && ks->value == value;
}

/* As per nm */
static char elf_type(const Elf_Sym *sym, const struct load_info *info)
{
    const Elf_Shdr *sechdrs = info->sechdrs;

    if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
        if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
            return 'v';
        else
            return 'w';
    }
    if (sym->st_shndx == SHN_UNDEF)
        return 'U';
    if (sym->st_shndx == SHN_ABS)
        return 'a';
    if (sym->st_shndx >= SHN_LORESERVE)
        return '?';
    if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
        return 't';
    if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
        && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
        if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
            return 'r';
        else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
            return 'g';
        else
            return 'd';
    }
    if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
        if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
            return 's';
        else
            return 'b';
    }
    if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name,
              ".debug")) {
        return 'n';
    }
    return '?';
}

static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
                           unsigned int shnum)
{
    const Elf_Shdr *sec;

    if (src->st_shndx == SHN_UNDEF
        || src->st_shndx >= shnum
        || !src->st_name)
        return false;

    sec = sechdrs + src->st_shndx;
    if (!(sec->sh_flags & SHF_ALLOC)
#ifndef CONFIG_KALLSYMS_ALL
        || !(sec->sh_flags & SHF_EXECINSTR)
#endif
        || (sec->sh_entsize & INIT_OFFSET_MASK))
        return false;

    return true;
}

/*
 * We only allocate and copy the strings needed by the parts of symtab
 * we keep.  This is simple, but has the effect of making multiple
 * copies of duplicates.  We could be more sophisticated, see
 * linux-kernel thread starting with
 * <73defb5e4bca04a6431392cc341112b1@localhost>.
 */
static void layout_symtab(struct module *mod, struct load_info *info)
{
    Elf_Shdr *symsect = info->sechdrs + info->index.sym;
    Elf_Shdr *strsect = info->sechdrs + info->index.str;
    const Elf_Sym *src;
    unsigned int i, nsrc, ndst, strtab_size;

    /* Put symbol section at end of init part of module. */
    symsect->sh_flags |= SHF_ALLOC;
    symsect->sh_entsize = get_offset(mod, &mod->init_size, symsect,
                     info->index.sym) | INIT_OFFSET_MASK;
    pr_debug("\t%s\n", info->secstrings + symsect->sh_name);

    src = (void *)info->hdr + symsect->sh_offset;
    nsrc = symsect->sh_size / sizeof(*src);

    /* strtab always starts with a nul, so offset 0 is the empty string. */
    strtab_size = 1;

    /* Compute total space required for the core symbols' strtab. */
    for (ndst = i = 0; i < nsrc; i++) {
        if (i == 0 ||
            is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
            strtab_size += strlen(&info->strtab[src[i].st_name])+1;
            ndst++;
        }
    }

    /* Append room for core symbols at end of core part. */
    info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
    info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
    mod->core_size += strtab_size;

    /* Put string table section at end of init part of module. */
    strsect->sh_flags |= SHF_ALLOC;
    strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
                     info->index.str) | INIT_OFFSET_MASK;
    pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
}

static void add_kallsyms(struct module *mod, const struct load_info *info)
{
    unsigned int i, ndst;
    const Elf_Sym *src;
    Elf_Sym *dst;
    char *s;
    Elf_Shdr *symsec = &info->sechdrs[info->index.sym];

    mod->symtab = (void *)symsec->sh_addr;
    mod->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
    /* Make sure we get permanent strtab: don't use info->strtab. */
    mod->strtab = (void *)info->sechdrs[info->index.str].sh_addr;

    /* Set types up while we still have access to sections. */
    for (i = 0; i < mod->num_symtab; i++)
        mod->symtab[i].st_info = elf_type(&mod->symtab[i], info);

    mod->core_symtab = dst = mod->module_core + info->symoffs;
    mod->core_strtab = s = mod->module_core + info->stroffs;
    src = mod->symtab;
    *s++ = 0;
    for (ndst = i = 0; i < mod->num_symtab; i++) {
        if (i == 0 ||
            is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
            dst[ndst] = src[i];
            dst[ndst++].st_name = s - mod->core_strtab;
            s += strlcpy(s, &mod->strtab[src[i].st_name],
                     KSYM_NAME_LEN) + 1;
        }
    }
    mod->core_num_syms = ndst;
}
#else
static inline void layout_symtab(struct module *mod, struct load_info *info)
{
}

static void add_kallsyms(struct module *mod, const struct load_info *info)
{
}
#endif /* CONFIG_KALLSYMS */

static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
{
    if (!debug)
        return;
#ifdef CONFIG_DYNAMIC_DEBUG
    if (ddebug_add_module(debug, num, debug->modname))
        printk(KERN_ERR "dynamic debug error adding module: %s\n",
                    debug->modname);
#endif
}

static void dynamic_debug_remove(struct _ddebug *debug)
{
    if (debug)
        ddebug_remove_module(debug->modname);
}

void * __weak module_alloc(unsigned long size)
{
    return size == 0 ? NULL : vmalloc_exec(size);
}

static void *module_alloc_update_bounds(unsigned long size)
{
    void *ret = module_alloc(size);

    if (ret) {
        mutex_lock(&module_mutex);
        /* Update module bounds. */
        if ((unsigned long)ret < module_addr_min)
            module_addr_min = (unsigned long)ret;
        if ((unsigned long)ret + size > module_addr_max)
            module_addr_max = (unsigned long)ret + size;
        mutex_unlock(&module_mutex);
    }
    return ret;
}

#ifdef CONFIG_DEBUG_KMEMLEAK
static void kmemleak_load_module(const struct module *mod,
                 const struct load_info *info)
{
    unsigned int i;

    /* only scan the sections containing data */
    kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);

    for (i = 1; i < info->hdr->e_shnum; i++) {
        const char *name = info->secstrings + info->sechdrs[i].sh_name;
        if (!(info->sechdrs[i].sh_flags & SHF_ALLOC))
            continue;
        if (!strstarts(name, ".data") && !strstarts(name, ".bss"))
            continue;

        kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
                   info->sechdrs[i].sh_size, GFP_KERNEL);
    }
}
#else
static inline void kmemleak_load_module(const struct module *mod,
                    const struct load_info *info)
{
}
#endif

#ifdef CONFIG_MODULE_SIG
static int module_sig_check(struct load_info *info,
                const void *mod, unsigned long *_len)
{
    int err = -ENOKEY;
    unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
    unsigned long len = *_len;

    if (len > markerlen &&
        memcmp(mod + len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
        /* We truncate the module to discard the signature */
        *_len -= markerlen;
        err = mod_verify_sig(mod, _len);
    }

    if (!err) {
        info->sig_ok = true;
        return 0;
    }

    /* Not having a signature is only an error if we're strict. */
    if (err < 0 && fips_enabled)
        panic("Module verification failed with error %d in FIPS mode\n",
              err);
    if (err == -ENOKEY && !sig_enforce)
        err = 0;

    return err;
}
#else /* !CONFIG_MODULE_SIG */
static int module_sig_check(struct load_info *info,
                void *mod, unsigned long *len)
{
    return 0;
}
#endif /* !CONFIG_MODULE_SIG */

/* Sets info->hdr, info->len and info->sig_ok. */
static int copy_and_check(struct load_info *info,
              const void __user *umod, unsigned long len,
              const char __user *uargs)
{
    int err;
    Elf_Ehdr *hdr;

    if (len < sizeof(*hdr))
        return -ENOEXEC;

    /* Suck in entire file: we'll want most of it. */
    if ((hdr = vmalloc(len)) == NULL)
        return -ENOMEM;

    if (copy_from_user(hdr, umod, len) != 0) {
        err = -EFAULT;
        goto free_hdr;
    }

    err = module_sig_check(info, hdr, &len);
    if (err)
        goto free_hdr;

    /* Sanity checks against insmoding binaries or wrong arch,
       weird elf version */
    if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
        || hdr->e_type != ET_REL
        || !elf_check_arch(hdr)
        || hdr->e_shentsize != sizeof(Elf_Shdr)) {
        err = -ENOEXEC;
        goto free_hdr;
    }

    if (hdr->e_shoff >= len ||
        hdr->e_shnum * sizeof(Elf_Shdr) > len - hdr->e_shoff) {
        err = -ENOEXEC;
        goto free_hdr;
    }

    info->hdr = hdr;
    info->len = len;
    return 0;

free_hdr:
    vfree(hdr);
    return err;
}

static void free_copy(struct load_info *info)
{
    vfree(info->hdr);
}

static int rewrite_section_headers(struct load_info *info)
{
    unsigned int i;

    /* This should always be true, but let's be sure. */
    info->sechdrs[0].sh_addr = 0;

    for (i = 1; i < info->hdr->e_shnum; i++) {
        Elf_Shdr *shdr = &info->sechdrs[i];
        if (shdr->sh_type != SHT_NOBITS
            && info->len < shdr->sh_offset + shdr->sh_size) {
            printk(KERN_ERR "Module len %lu truncated\n",
                   info->len);
            return -ENOEXEC;
        }

        /* Mark all sections sh_addr with their address in the
           temporary image. */
        shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;

#ifndef CONFIG_MODULE_UNLOAD
        /* Don't load .exit sections */
        if (strstarts(info->secstrings+shdr->sh_name, ".exit"))
            shdr->sh_flags &= ~(unsigned long)SHF_ALLOC;
#endif
    }

    /* Track but don't keep modinfo and version sections. */
    info->index.vers = find_sec(info, "__versions");
    info->index.info = find_sec(info, ".modinfo");
    info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
    info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
    return 0;
}

/*
 * Set up our basic convenience variables (pointers to section headers,
 * search for module section index etc), and do some basic section
 * verification.
 *
 * Return the temporary module pointer (we'll replace it with the final
 * one when we move the module sections around).
 */
static struct module *setup_load_info(struct load_info *info)
{
    unsigned int i;
    int err;
    struct module *mod;

    /* Set up the convenience variables */
    info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
    info->secstrings = (void *)info->hdr
        + info->sechdrs[info->hdr->e_shstrndx].sh_offset;

    err = rewrite_section_headers(info);
    if (err)
        return ERR_PTR(err);

    /* Find internal symbols and strings. */
    for (i = 1; i < info->hdr->e_shnum; i++) {
        if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
            info->index.sym = i;
            info->index.str = info->sechdrs[i].sh_link;
            info->strtab = (char *)info->hdr
                + info->sechdrs[info->index.str].sh_offset;
            break;
        }
    }

    info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
    if (!info->index.mod) {
        printk(KERN_WARNING "No module found in object\n");
        return ERR_PTR(-ENOEXEC);
    }
    /* This is temporary: point mod into copy of data. */
    mod = (void *)info->sechdrs[info->index.mod].sh_addr;

    if (info->index.sym == 0) {
        printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
               mod->name);
        return ERR_PTR(-ENOEXEC);
    }

    info->index.pcpu = find_pcpusec(info);

    /* Check module struct version now, before we try to use module. */
    if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
        return ERR_PTR(-ENOEXEC);

    return mod;
}

static int check_modinfo(struct module *mod, struct load_info *info)
{
    const char *modmagic = get_modinfo(info, "vermagic");
    int err;

    /* This is allowed: modprobe --force will invalidate it. */
    if (!modmagic) {
        err = try_to_force_load(mod, "bad vermagic");
        if (err)
            return err;
    } else if (!same_magic(modmagic, vermagic, info->index.vers)) {
        printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
               mod->name, modmagic, vermagic);
        return -ENOEXEC;
    }

    if (!get_modinfo(info, "intree"))
        add_taint_module(mod, TAINT_OOT_MODULE);

    if (get_modinfo(info, "staging")) {
        add_taint_module(mod, TAINT_CRAP);
        printk(KERN_WARNING "%s: module is from the staging directory,"
               " the quality is unknown, you have been warned.\n",
               mod->name);
    }

    /* Set up license info based on the info section */
    set_license(mod, get_modinfo(info, "license"));

    return 0;
}

static void find_module_sections(struct module *mod, struct load_info *info)
{
    mod->kp = section_objs(info, "__param",
                   sizeof(*mod->kp), &mod->num_kp);
    mod->syms = section_objs(info, "__ksymtab",
                 sizeof(*mod->syms), &mod->num_syms);
    mod->crcs = section_addr(info, "__kcrctab");
    mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
                     sizeof(*mod->gpl_syms),
                     &mod->num_gpl_syms);
    mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
    mod->gpl_future_syms = section_objs(info,
                        "__ksymtab_gpl_future",
                        sizeof(*mod->gpl_future_syms),
                        &mod->num_gpl_future_syms);
    mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");

#ifdef CONFIG_UNUSED_SYMBOLS
    mod->unused_syms = section_objs(info, "__ksymtab_unused",
                    sizeof(*mod->unused_syms),
                    &mod->num_unused_syms);
    mod->unused_crcs = section_addr(info, "__kcrctab_unused");
    mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
                        sizeof(*mod->unused_gpl_syms),
                        &mod->num_unused_gpl_syms);
    mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
#endif
#ifdef CONFIG_CONSTRUCTORS
    mod->ctors = section_objs(info, ".ctors",
                  sizeof(*mod->ctors), &mod->num_ctors);
#endif

#ifdef CONFIG_TRACEPOINTS
    mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
                         sizeof(*mod->tracepoints_ptrs),
                         &mod->num_tracepoints);
#endif
#ifdef HAVE_JUMP_LABEL
    mod->jump_entries = section_objs(info, "__jump_table",
                    sizeof(*mod->jump_entries),
                    &mod->num_jump_entries);
#endif
#ifdef CONFIG_EVENT_TRACING
    mod->trace_events = section_objs(info, "_ftrace_events",
                     sizeof(*mod->trace_events),
                     &mod->num_trace_events);
    /*
     * This section contains pointers to allocated objects in the trace
     * code and not scanning it leads to false positives.
     */
    kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
               mod->num_trace_events, GFP_KERNEL);
#endif
#ifdef CONFIG_TRACING
    mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
                     sizeof(*mod->trace_bprintk_fmt_start),
                     &mod->num_trace_bprintk_fmt);
    /*
     * This section contains pointers to allocated objects in the trace
     * code and not scanning it leads to false positives.
     */
    kmemleak_scan_area(mod->trace_bprintk_fmt_start,
               sizeof(*mod->trace_bprintk_fmt_start) *
               mod->num_trace_bprintk_fmt, GFP_KERNEL);
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
    /* sechdrs[0].sh_size is always zero */
    mod->ftrace_callsites = section_objs(info, "__mcount_loc",
                         sizeof(*mod->ftrace_callsites),
                         &mod->num_ftrace_callsites);
#endif

    mod->extable = section_objs(info, "__ex_table",
                    sizeof(*mod->extable), &mod->num_exentries);

    if (section_addr(info, "__obsparm"))
        printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
               mod->name);

    info->debug = section_objs(info, "__verbose",
                   sizeof(*info->debug), &info->num_debug);
}

static int move_module(struct module *mod, struct load_info *info)
{
    int i;
    void *ptr;

    /* Do the allocs. */
    ptr = module_alloc_update_bounds(mod->core_size);
    /*
     * The pointer to this block is stored in the module structure
     * which is inside the block. Just mark it as not being a
     * leak.
     */
    kmemleak_not_leak(ptr);
    if (!ptr)
        return -ENOMEM;

    memset(ptr, 0, mod->core_size);
    mod->module_core = ptr;

    ptr = module_alloc_update_bounds(mod->init_size);
    /*
     * The pointer to this block is stored in the module structure
     * which is inside the block. This block doesn't need to be
     * scanned as it contains data and code that will be freed
     * after the module is initialized.
     */
    kmemleak_ignore(ptr);
    if (!ptr && mod->init_size) {
        module_free(mod, mod->module_core);
        return -ENOMEM;
    }
    memset(ptr, 0, mod->init_size);
    mod->module_init = ptr;

    /* Transfer each section which specifies SHF_ALLOC */
    pr_debug("final section addresses:\n");
    for (i = 0; i < info->hdr->e_shnum; i++) {
        void *dest;
        Elf_Shdr *shdr = &info->sechdrs[i];

        if (!(shdr->sh_flags & SHF_ALLOC))
            continue;

        if (shdr->sh_entsize & INIT_OFFSET_MASK)
            dest = mod->module_init
                + (shdr->sh_entsize & ~INIT_OFFSET_MASK);
        else
            dest = mod->module_core + shdr->sh_entsize;

        if (shdr->sh_type != SHT_NOBITS)
            memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
        /* Update sh_addr to point to copy in image. */
        shdr->sh_addr = (unsigned long)dest;
        pr_debug("\t0x%lx %s\n",
             (long)shdr->sh_addr, info->secstrings + shdr->sh_name);
    }

    return 0;
}

static int check_module_license_and_versions(struct module *mod)
{
    /*
     * ndiswrapper is under GPL by itself, but loads proprietary modules.
     * Don't use add_taint_module(), as it would prevent ndiswrapper from
     * using GPL-only symbols it needs.
     */
    if (strcmp(mod->name, "ndiswrapper") == 0)
        add_taint(TAINT_PROPRIETARY_MODULE);

    /* driverloader was caught wrongly pretending to be under GPL */
    if (strcmp(mod->name, "driverloader") == 0)
        add_taint_module(mod, TAINT_PROPRIETARY_MODULE);

    /* lve claims to be GPL but upstream won't provide source */
    if (strcmp(mod->name, "lve") == 0)
        add_taint_module(mod, TAINT_PROPRIETARY_MODULE);

#ifdef CONFIG_MODVERSIONS
    if ((mod->num_syms && !mod->crcs)
        || (mod->num_gpl_syms && !mod->gpl_crcs)
        || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
#ifdef CONFIG_UNUSED_SYMBOLS
        || (mod->num_unused_syms && !mod->unused_crcs)
        || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
#endif
        ) {
        return try_to_force_load(mod,
                     "no versions for exported symbols");
    }
#endif
    return 0;
}

static void flush_module_icache(const struct module *mod)
{
    mm_segment_t old_fs;

    /* flush the icache in correct context */
    old_fs = get_fs();
    set_fs(KERNEL_DS);

    /*
     * Flush the instruction cache, since we've played with text.
     * Do it before processing of module parameters, so the module
     * can provide parameter accessor functions of its own.
     */
    if (mod->module_init)
        flush_icache_range((unsigned long)mod->module_init,
                   (unsigned long)mod->module_init
                   + mod->init_size);
    flush_icache_range((unsigned long)mod->module_core,
               (unsigned long)mod->module_core + mod->core_size);

    set_fs(old_fs);
}

int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
                     Elf_Shdr *sechdrs,
                     char *secstrings,
                     struct module *mod)
{
    return 0;
}

static struct module *layout_and_allocate(struct load_info *info)
{
    /* Module within temporary copy. */
    struct module *mod;
    Elf_Shdr *pcpusec;
    int err;

    mod = setup_load_info(info);
    if (IS_ERR(mod))
        return mod;

    err = check_modinfo(mod, info);
    if (err)
        return ERR_PTR(err);

    /* Allow arches to frob section contents and sizes.  */
    err = module_frob_arch_sections(info->hdr, info->sechdrs,
                    info->secstrings, mod);
    if (err < 0)
        goto out;

    pcpusec = &info->sechdrs[info->index.pcpu];
    if (pcpusec->sh_size) {
        /* We have a special allocation for this section. */
        err = percpu_modalloc(mod,
                      pcpusec->sh_size, pcpusec->sh_addralign);
        if (err)
            goto out;
        pcpusec->sh_flags &= ~(unsigned long)SHF_ALLOC;
    }

    /* Determine total sizes, and put offsets in sh_entsize.  For now
       this is done generically; there doesn't appear to be any
       special cases for the architectures. */
    layout_sections(mod, info);
    layout_symtab(mod, info);

    /* Allocate and move to the final place */
    err = move_module(mod, info);
    if (err)
        goto free_percpu;

    /* Module has been copied to its final place now: return it. */
    mod = (void *)info->sechdrs[info->index.mod].sh_addr;
    kmemleak_load_module(mod, info);
    return mod;

free_percpu:
    percpu_modfree(mod);
out:
    return ERR_PTR(err);
}

/* mod is no longer valid after this! */
static void module_deallocate(struct module *mod, struct load_info *info)
{
    percpu_modfree(mod);
    module_free(mod, mod->module_init);
    module_free(mod, mod->module_core);
}

int __weak module_finalize(const Elf_Ehdr *hdr,
               const Elf_Shdr *sechdrs,
               struct module *me)
{
    return 0;
}

static int post_relocation(struct module *mod, const struct load_info *info)
{
    /* Sort exception table now relocations are done. */
    sort_extable(mod->extable, mod->extable + mod->num_exentries);

    /* Copy relocated percpu area over. */
    percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
               info->sechdrs[info->index.pcpu].sh_size);

    /* Setup kallsyms-specific fields. */
    add_kallsyms(mod, info);

    /* Arch-specific module finalizing. */
    return module_finalize(info->hdr, info->sechdrs, mod);
}

/* Is this module of this name done loading?  No locks held. */
static bool finished_loading(const char *name)
{
    struct module *mod;
    bool ret;

    mutex_lock(&module_mutex);
    mod = find_module(name);
    ret = !mod || mod->state != MODULE_STATE_COMING;
    mutex_unlock(&module_mutex);

    return ret;
}

/* Allocate and load the module: note that size of section 0 is always
   zero, and we rely on this for optional sections. */
static struct module *load_module(void __user *umod,
                  unsigned long len,
                  const char __user *uargs)
{
    struct load_info info = { NULL, };
    struct module *mod, *old;
    long err;

    pr_debug("load_module: umod=%p, len=%lu, uargs=%p\n",
           umod, len, uargs);

    /* Copy in the blobs from userspace, check they are vaguely sane. */
    err = copy_and_check(&info, umod, len, uargs);
    if (err)
        return ERR_PTR(err);

    /* Figure out module layout, and allocate all the memory. */
    mod = layout_and_allocate(&info);
    if (IS_ERR(mod)) {
        err = PTR_ERR(mod);
        goto free_copy;
    }

#ifdef CONFIG_MODULE_SIG
    mod->sig_ok = info.sig_ok;
    if (!mod->sig_ok)
        add_taint_module(mod, TAINT_FORCED_MODULE);
#endif

    /* Now module is in final location, initialize linked lists, etc. */
    err = module_unload_init(mod);
    if (err)
        goto free_module;

    /* Now we've got everything in the final locations, we can
     * find optional sections. */
    find_module_sections(mod, &info);

    err = check_module_license_and_versions(mod);
    if (err)
        goto free_unload;

    /* Set up MODINFO_ATTR fields */
    setup_modinfo(mod, &info);

    /* Fix up syms, so that st_value is a pointer to location. */
    err = simplify_symbols(mod, &info);
    if (err < 0)
        goto free_modinfo;

    err = apply_relocations(mod, &info);
    if (err < 0)
        goto free_modinfo;

    err = post_relocation(mod, &info);
    if (err < 0)
        goto free_modinfo;

    flush_module_icache(mod);

    /* Now copy in args */
    mod->args = strndup_user(uargs, ~0UL >> 1);
    if (IS_ERR(mod->args)) {
        err = PTR_ERR(mod->args);
        goto free_arch_cleanup;
    }

    /* Mark state as coming so strong_try_module_get() ignores us. */
    mod->state = MODULE_STATE_COMING;

    /* Now sew it into the lists so we can get lockdep and oops
     * info during argument parsing.  No one should access us, since
     * strong_try_module_get() will fail.
     * lockdep/oops can run asynchronous, so use the RCU list insertion
     * function to insert in a way safe to concurrent readers.
     * The mutex protects against concurrent writers.
     */
again:
    mutex_lock(&module_mutex);
    if ((old = find_module(mod->name)) != NULL) {
        if (old->state == MODULE_STATE_COMING) {
            /* Wait in case it fails to load. */
            mutex_unlock(&module_mutex);
            err = wait_event_interruptible(module_wq,
                           finished_loading(mod->name));
            if (err)
                goto free_arch_cleanup;
            goto again;
        }
        err = -EEXIST;
        goto unlock;
    }

    /* This has to be done once we're sure module name is unique. */
    dynamic_debug_setup(info.debug, info.num_debug);

    /* Find duplicate symbols */
    err = verify_export_symbols(mod);
    if (err < 0)
        goto ddebug;

    module_bug_finalize(info.hdr, info.sechdrs, mod);
    list_add_rcu(&mod->list, &modules);
    mutex_unlock(&module_mutex);

    /* Module is ready to execute: parsing args may do that. */
    err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
             -32768, 32767, &ddebug_dyndbg_module_param_cb);
    if (err < 0)
        goto unlink;

    /* Link in to syfs. */
    err = mod_sysfs_setup(mod, &info, mod->kp, mod->num_kp);
    if (err < 0)
        goto unlink;

    /* Get rid of temporary copy. */
    free_copy(&info);

    /* Done! */
    trace_module_load(mod);
    return mod;

 unlink:
    mutex_lock(&module_mutex);
    /* Unlink carefully: kallsyms could be walking list. */
    list_del_rcu(&mod->list);
    module_bug_cleanup(mod);
    wake_up_all(&module_wq);
 ddebug:
    dynamic_debug_remove(info.debug);
 unlock:
    mutex_unlock(&module_mutex);
    synchronize_sched();
    kfree(mod->args);
 free_arch_cleanup:
    module_arch_cleanup(mod);
 free_modinfo:
    free_modinfo(mod);
 free_unload:
    module_unload_free(mod);
 free_module:
    module_deallocate(mod, &info);
 free_copy:
    free_copy(&info);
    return ERR_PTR(err);
}

/* Call module constructors. */
static void do_mod_ctors(struct module *mod)
{
#ifdef CONFIG_CONSTRUCTORS
    unsigned long i;

    for (i = 0; i < mod->num_ctors; i++)
        mod->ctors[i]();
#endif
}

/* This is where the real work happens */
SYSCALL_DEFINE3(init_module, void __user *, umod,
        unsigned long, len, const char __user *, uargs)
{
    struct module *mod;
    int ret = 0;

    /* Must have permission */
    if (!capable(CAP_SYS_MODULE) || modules_disabled)
        return -EPERM;

    /* Do all the hard work */
    mod = load_module(umod, len, uargs);
    if (IS_ERR(mod))
        return PTR_ERR(mod);

    blocking_notifier_call_chain(&module_notify_list,
            MODULE_STATE_COMING, mod);

    /* Set RO and NX regions for core */
    set_section_ro_nx(mod->module_core,
                mod->core_text_size,
                mod->core_ro_size,
                mod->core_size);

    /* Set RO and NX regions for init */
    set_section_ro_nx(mod->module_init,
                mod->init_text_size,
                mod->init_ro_size,
                mod->init_size);

    do_mod_ctors(mod);
    /* Start the module */
    if (mod->init != NULL)
        ret = do_one_initcall(mod->init);
    if (ret < 0) {
        /* Init routine failed: abort.  Try to protect us from
                   buggy refcounters. */
        mod->state = MODULE_STATE_GOING;
        synchronize_sched();
        module_put(mod);
        blocking_notifier_call_chain(&module_notify_list,
                         MODULE_STATE_GOING, mod);
        free_module(mod);
        wake_up_all(&module_wq);
        return ret;
    }
    if (ret > 0) {
        printk(KERN_WARNING
"%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n"
"%s: loading module anyway...\n",
               __func__, mod->name, ret,
               __func__);
        dump_stack();
    }

    /* Now it's a first class citizen! */
    mod->state = MODULE_STATE_LIVE;
    blocking_notifier_call_chain(&module_notify_list,
                     MODULE_STATE_LIVE, mod);

    /* We need to finish all async code before the module init sequence is done */
    async_synchronize_full();

    mutex_lock(&module_mutex);
    /* Drop initial reference. */
    module_put(mod);
    trim_init_extable(mod);
#ifdef CONFIG_KALLSYMS
    mod->num_symtab = mod->core_num_syms;
    mod->symtab = mod->core_symtab;
    mod->strtab = mod->core_strtab;
#endif
    unset_module_init_ro_nx(mod);
    module_free(mod, mod->module_init);
    mod->module_init = NULL;
    mod->init_size = 0;
    mod->init_ro_size = 0;
    mod->init_text_size = 0;
    mutex_unlock(&module_mutex);
    wake_up_all(&module_wq);

    return 0;
}

static inline int within(unsigned long addr, void *start, unsigned long size)
{
    return ((void *)addr >= start && (void *)addr < start + size);
}

#ifdef CONFIG_KALLSYMS
/*
 * This ignores the intensely annoying "mapping symbols" found
 * in ARM ELF files: $a, $t and $d.
 */
static inline int is_arm_mapping_symbol(const char *str)
{
    return str[0] == '$' && strchr("atd", str[1])
           && (str[2] == '\0' || str[2] == '.');
}

static const char *get_ksymbol(struct module *mod,
                   unsigned long addr,
                   unsigned long *size,
                   unsigned long *offset)
{
    unsigned int i, best = 0;
    unsigned long nextval;

    /* At worse, next value is at end of module */
    if (within_module_init(addr, mod))
        nextval = (unsigned long)mod->module_init+mod->init_text_size;
    else
        nextval = (unsigned long)mod->module_core+mod->core_text_size;

    /* Scan for closest preceding symbol, and next symbol. (ELF
       starts real symbols at 1). */
    for (i = 1; i < mod->num_symtab; i++) {
        if (mod->symtab[i].st_shndx == SHN_UNDEF)
            continue;

        /* We ignore unnamed symbols: they're uninformative
         * and inserted at a whim. */
        if (mod->symtab[i].st_value <= addr
            && mod->symtab[i].st_value > mod->symtab[best].st_value
            && *(mod->strtab + mod->symtab[i].st_name) != '\0'
            && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
            best = i;
        if (mod->symtab[i].st_value > addr
            && mod->symtab[i].st_value < nextval
            && *(mod->strtab + mod->symtab[i].st_name) != '\0'
            && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
            nextval = mod->symtab[i].st_value;
    }

    if (!best)
        return NULL;

    if (size)
        *size = nextval - mod->symtab[best].st_value;
    if (offset)
        *offset = addr - mod->symtab[best].st_value;
    return mod->strtab + mod->symtab[best].st_name;
}

/* For kallsyms to ask for address resolution.  NULL means not found.  Careful
 * not to lock to avoid deadlock on oopses, simply disable preemption. */
const char *module_address_lookup(unsigned long addr,
                unsigned long *size,
                unsigned long *offset,
                char **modname,
                char *namebuf)
{
    struct module *mod;
    const char *ret = NULL;

    preempt_disable();
    list_for_each_entry_rcu(mod, &modules, list) {
        if (within_module_init(addr, mod) ||
            within_module_core(addr, mod)) {
            if (modname)
                *modname = mod->name;
            ret = get_ksymbol(mod, addr, size, offset);
            break;
        }
    }
    /* Make a copy in here where it's safe */
    if (ret) {
        strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
        ret = namebuf;
    }
    preempt_enable();
    return ret;
}

int lookup_module_symbol_name(unsigned long addr, char *symname)
{
    struct module *mod;

    preempt_disable();
    list_for_each_entry_rcu(mod, &modules, list) {
        if (within_module_init(addr, mod) ||
            within_module_core(addr, mod)) {
            const char *sym;

            sym = get_ksymbol(mod, addr, NULL, NULL);
            if (!sym)
                goto out;
            strlcpy(symname, sym, KSYM_NAME_LEN);
            preempt_enable();
            return 0;
        }
    }
out:
    preempt_enable();
    return -ERANGE;
}

int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
            unsigned long *offset, char *modname, char *name)
{
    struct module *mod;

    preempt_disable();
    list_for_each_entry_rcu(mod, &modules, list) {
        if (within_module_init(addr, mod) ||
            within_module_core(addr, mod)) {
            const char *sym;

            sym = get_ksymbol(mod, addr, size, offset);
            if (!sym)
                goto out;
            if (modname)
                strlcpy(modname, mod->name, MODULE_NAME_LEN);
            if (name)
                strlcpy(name, sym, KSYM_NAME_LEN);
            preempt_enable();
            return 0;
        }
    }
out:
    preempt_enable();
    return -ERANGE;
}

int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
            char *name, char *module_name, int *exported)
{
    struct module *mod;

    preempt_disable();
    list_for_each_entry_rcu(mod, &modules, list) {
        if (symnum < mod->num_symtab) {
            *value = mod->symtab[symnum].st_value;
            *type = mod->symtab[symnum].st_info;
            strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
                KSYM_NAME_LEN);
            strlcpy(module_name, mod->name, MODULE_NAME_LEN);
            *exported = is_exported(name, *value, mod);
            preempt_enable();
            return 0;
        }
        symnum -= mod->num_symtab;
    }
    preempt_enable();
    return -ERANGE;
}

static unsigned long mod_find_symname(struct module *mod, const char *name)
{
    unsigned int i;

    for (i = 0; i < mod->num_symtab; i++)
        if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
            mod->symtab[i].st_info != 'U')
            return mod->symtab[i].st_value;
    return 0;
}

/* Look for this name: can be of form module:name. */
unsigned long module_kallsyms_lookup_name(const char *name)
{
    struct module *mod;
    char *colon;
    unsigned long ret = 0;

    /* Don't lock: we're in enough trouble already. */
    preempt_disable();
    if ((colon = strchr(name, ':')) != NULL) {
        *colon = '\0';
        if ((mod = find_module(name)) != NULL)
            ret = mod_find_symname(mod, colon+1);
        *colon = ':';
    } else {
        list_for_each_entry_rcu(mod, &modules, list)
            if ((ret = mod_find_symname(mod, name)) != 0)
                break;
    }
    preempt_enable();
    return ret;
}

int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
                         struct module *, unsigned long),
                   void *data)
{
    struct module *mod;
    unsigned int i;
    int ret;

    list_for_each_entry(mod, &modules, list) {
        for (i = 0; i < mod->num_symtab; i++) {
            ret = fn(data, mod->strtab + mod->symtab[i].st_name,
                 mod, mod->symtab[i].st_value);
            if (ret != 0)
                return ret;
        }
    }
    return 0;
}
#endif /* CONFIG_KALLSYMS */

static char *module_flags(struct module *mod, char *buf)
{
    int bx = 0;

    if (mod->taints ||
        mod->state == MODULE_STATE_GOING ||
        mod->state == MODULE_STATE_COMING) {
        buf[bx++] = '(';
        bx += module_flags_taint(mod, buf + bx);
        /* Show a - for module-is-being-unloaded */
        if (mod->state == MODULE_STATE_GOING)
            buf[bx++] = '-';
        /* Show a + for module-is-being-loaded */
        if (mod->state == MODULE_STATE_COMING)
            buf[bx++] = '+';
        buf[bx++] = ')';
    }
    buf[bx] = '\0';

    return buf;
}

#ifdef CONFIG_PROC_FS
/* Called by the /proc file system to return a list of modules. */
static void *m_start(struct seq_file *m, loff_t *pos)
{
    mutex_lock(&module_mutex);
    return seq_list_start(&modules, *pos);
}

static void *m_next(struct seq_file *m, void *p, loff_t *pos)
{
    return seq_list_next(p, &modules, pos);
}

static void m_stop(struct seq_file *m, void *p)
{
    mutex_unlock(&module_mutex);
}

static int m_show(struct seq_file *m, void *p)
{
    struct module *mod = list_entry(p, struct module, list);
    char buf[8];

    seq_printf(m, "%s %u",
           mod->name, mod->init_size + mod->core_size);
    print_unload_info(m, mod);

    /* Informative for users. */
    seq_printf(m, " %s",
           mod->state == MODULE_STATE_GOING ? "Unloading":
           mod->state == MODULE_STATE_COMING ? "Loading":
           "Live");
    /* Used by oprofile and other similar tools. */
    seq_printf(m, " 0x%pK", mod->module_core);

    /* Taints info */
    if (mod->taints)
        seq_printf(m, " %s", module_flags(mod, buf));

    seq_printf(m, "\n");
    return 0;
}

/* Format: modulename size refcount deps address

   Where refcount is a number or -, and deps is a comma-separated list
   of depends or -.
*/
static const struct seq_operations modules_op = {
    .start  = m_start,
    .next   = m_next,
    .stop   = m_stop,
    .show   = m_show
};

static int modules_open(struct inode *inode, struct file *file)
{
    return seq_open(file, &modules_op);
}

static const struct file_operations proc_modules_operations = {
    .open       = modules_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = seq_release,
};

static int __init proc_modules_init(void)
{
    proc_create("modules", 0, NULL, &proc_modules_operations);
    return 0;
}
module_init(proc_modules_init);
#endif

/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_extables(unsigned long addr)
{
    const struct exception_table_entry *e = NULL;
    struct module *mod;

    preempt_disable();
    list_for_each_entry_rcu(mod, &modules, list) {
        if (mod->num_exentries == 0)
            continue;

        e = search_extable(mod->extable,
                   mod->extable + mod->num_exentries - 1,
                   addr);
        if (e)
            break;
    }
    preempt_enable();

    /* Now, if we found one, we are running inside it now, hence
       we cannot unload the module, hence no refcnt needed. */
    return e;
}

/*
 * is_module_address - is this address inside a module?
 * @addr: the address to check.
 *
 * See is_module_text_address() if you simply want to see if the address
 * is code (not data).
 */
bool is_module_address(unsigned long addr)
{
    bool ret;

    preempt_disable();
    ret = __module_address(addr) != NULL;
    preempt_enable();

    return ret;
}

/*
 * __module_address - get the module which contains an address.
 * @addr: the address.
 *
 * Must be called with preempt disabled or module mutex held so that
 * module doesn't get freed during this.
 */
struct module *__module_address(unsigned long addr)
{
    struct module *mod;

    if (addr < module_addr_min || addr > module_addr_max)
        return NULL;

    list_for_each_entry_rcu(mod, &modules, list)
        if (within_module_core(addr, mod)
            || within_module_init(addr, mod))
            return mod;
    return NULL;
}
EXPORT_SYMBOL_GPL(__module_address);

/*
 * is_module_text_address - is this address inside module code?
 * @addr: the address to check.
 *
 * See is_module_address() if you simply want to see if the address is
 * anywhere in a module.  See kernel_text_address() for testing if an
 * address corresponds to kernel or module code.
 */
bool is_module_text_address(unsigned long addr)
{
    bool ret;

    preempt_disable();
    ret = __module_text_address(addr) != NULL;
    preempt_enable();

    return ret;
}

/*
 * __module_text_address - get the module whose code contains an address.
 * @addr: the address.
 *
 * Must be called with preempt disabled or module mutex held so that
 * module doesn't get freed during this.
 */
struct module *__module_text_address(unsigned long addr)
{
    struct module *mod = __module_address(addr);
    if (mod) {
        /* Make sure it's within the text section. */
        if (!within(addr, mod->module_init, mod->init_text_size)
            && !within(addr, mod->module_core, mod->core_text_size))
            mod = NULL;
    }
    return mod;
}
EXPORT_SYMBOL_GPL(__module_text_address);

/* Don't grab lock, we're oopsing. */
void print_modules(void)
{
    struct module *mod;
    char buf[8];

    printk(KERN_DEFAULT "Modules linked in:");
    /* Most callers should already have preempt disabled, but make sure */
    preempt_disable();
    list_for_each_entry_rcu(mod, &modules, list)
        printk(" %s%s", mod->name, module_flags(mod, buf));
    preempt_enable();
    if (last_unloaded_module[0])
        printk(" [last unloaded: %s]", last_unloaded_module);
    printk("\n");
}

#ifdef CONFIG_MODVERSIONS
/* Generate the signature for all relevant module structures here.
 * If these change, we don't want to try to parse the module. */
void module_layout(struct module *mod,
           struct modversion_info *ver,
           struct kernel_param *kp,
           struct kernel_symbol *ks,
           struct tracepoint * const *tp)
{
}
EXPORT_SYMBOL(module_layout);
#endif