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    Subject[PATCH 2.6.20-rc1 04/10] Modules support for kmemleak
    Date
    This patch handles the kmemleak operations needed for modules loading so
    that memory allocations from inside a module are properly tracked.

    Signed-off-by: Catalin Marinas <catalin.marinas@gmail.com>
    ---

    kernel/module.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 56 insertions(+), 0 deletions(-)

    diff --git a/kernel/module.c b/kernel/module.c
    index b565eae..f1ff3f5 100644
    --- a/kernel/module.c
    +++ b/kernel/module.c
    @@ -345,6 +345,7 @@ static void *percpu_modalloc(unsigned lo
    unsigned long extra;
    unsigned int i;
    void *ptr;
    + int cpu;

    if (align > SMP_CACHE_BYTES) {
    printk(KERN_WARNING "%s: per-cpu alignment %li > %i\n",
    @@ -374,6 +375,10 @@ static void *percpu_modalloc(unsigned lo
    if (!split_block(i, size))
    return NULL;

    + /* add the per-cpu scanning areas */
    + for_each_possible_cpu(cpu)
    + memleak_alloc(ptr + per_cpu_offset(cpu), size, 0);
    +
    /* Mark allocated */
    pcpu_size[i] = -pcpu_size[i];
    return ptr;
    @@ -388,6 +393,7 @@ static void percpu_modfree(void *freeme)
    {
    unsigned int i;
    void *ptr = __per_cpu_start + block_size(pcpu_size[0]);
    + int cpu;

    /* First entry is core kernel percpu data. */
    for (i = 1; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
    @@ -399,6 +405,10 @@ static void percpu_modfree(void *freeme)
    BUG();

    free:
    + /* remove the per-cpu scanning areas */
    + for_each_possible_cpu(cpu)
    + memleak_free(freeme + per_cpu_offset(cpu));
    +
    /* Merge with previous? */
    if (pcpu_size[i-1] >= 0) {
    pcpu_size[i-1] += pcpu_size[i];
    @@ -1529,6 +1539,42 @@ static inline void add_kallsyms(struct m
    }
    #endif /* CONFIG_KALLSYMS */

    +#ifdef CONFIG_DEBUG_MEMLEAK
    +static void memleak_load_module(struct module *mod, Elf_Ehdr *hdr,
    + Elf_Shdr *sechdrs, char *secstrings)
    +{
    + unsigned int mloffindex, i;
    +
    + /* insert any new pointer aliases */
    + mloffindex = find_sec(hdr, sechdrs, secstrings, ".init.memleak_offsets");
    + if (mloffindex)
    + memleak_insert_aliases((void *)sechdrs[mloffindex].sh_addr,
    + (void *)sechdrs[mloffindex].sh_addr
    + + sechdrs[mloffindex].sh_size);
    +
    + /* only scan the sections containing data */
    + memleak_scan_area(mod->module_core,
    + (unsigned long)mod - (unsigned long)mod->module_core,
    + sizeof(struct module));
    +
    + for (i = 1; i < hdr->e_shnum; i++) {
    + if (!(sechdrs[i].sh_flags & SHF_ALLOC))
    + continue;
    + if (strncmp(secstrings + sechdrs[i].sh_name, ".data", 5) != 0
    + && strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) != 0)
    + continue;
    +
    + memleak_scan_area(mod->module_core,
    + sechdrs[i].sh_addr - (unsigned long)mod->module_core,
    + sechdrs[i].sh_size);
    + }
    +}
    +#else
    +static inline void memleak_load_module(struct module *mod, Elf_Ehdr *hdr,
    + Elf_Shdr *sechdrs, char *secstrings)
    +{ }
    +#endif
    +
    /* 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,
    @@ -1724,6 +1770,10 @@ static struct module *load_module(void _

    /* Do the allocs. */
    ptr = module_alloc(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 */
    + memleak_not_leak(ptr);
    if (!ptr) {
    err = -ENOMEM;
    goto free_percpu;
    @@ -1732,6 +1782,11 @@ static struct module *load_module(void _
    mod->module_core = ptr;

    ptr = module_alloc(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 */
    + memleak_ignore(ptr);
    if (!ptr && mod->init_size) {
    err = -ENOMEM;
    goto free_core;
    @@ -1762,6 +1817,7 @@ static struct module *load_module(void _
    }
    /* Module has been moved. */
    mod = (void *)sechdrs[modindex].sh_addr;
    + memleak_load_module(mod, hdr, sechdrs, secstrings);

    /* Now we've moved module, initialize linked lists, etc. */
    module_unload_init(mod);
    -
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