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Commit 4f2294b6 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

kmemleak: Add modules support 



This patch handles the kmemleak operations needed for modules loading so
that memory allocations from inside a module are properly tracked.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent dbb1f81c

kernel/module.c

+56 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ 
#include <linux/ftrace.h>

#include <linux/async.h>

#include <linux/percpu.h>

#include <linux/kmemleak.h>



#if 0

#define DEBUGP printk
@@ -430,6 +431,7 @@ static void *percpu_modalloc(unsigned long size, unsigned long align, 
	unsigned long extra;

	unsigned int i;

	void *ptr;

	int cpu;



	if (align > PAGE_SIZE) {

		printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
@@ -459,6 +461,11 @@ static void *percpu_modalloc(unsigned long size, unsigned long align, 
			if (!split_block(i, size))

				return NULL;



		/* add the per-cpu scanning areas */

		for_each_possible_cpu(cpu)

			kmemleak_alloc(ptr + per_cpu_offset(cpu), size, 0,

				       GFP_KERNEL);



		/* Mark allocated */

		pcpu_size[i] = -pcpu_size[i];

		return ptr;
@@ -473,6 +480,7 @@ 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++) {
@@ -484,6 +492,10 @@ static void percpu_modfree(void *freeme) 
	BUG();



 free:

	/* remove the per-cpu scanning areas */

	for_each_possible_cpu(cpu)

		kmemleak_free(freeme + per_cpu_offset(cpu));



	/* Merge with previous? */

	if (pcpu_size[i-1] >= 0) {

		pcpu_size[i-1] += pcpu_size[i];
@@ -1876,6 +1888,36 @@ static void *module_alloc_update_bounds(unsigned long size) 
	return ret;

}



#ifdef CONFIG_DEBUG_KMEMLEAK

static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,

				 Elf_Shdr *sechdrs, char *secstrings)

{

	unsigned int i;



	/* only scan the sections containing data */

	kmemleak_scan_area(mod->module_core, (unsigned long)mod -

			   (unsigned long)mod->module_core,

			   sizeof(struct module), GFP_KERNEL);



	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;



		kmemleak_scan_area(mod->module_core, sechdrs[i].sh_addr -

				   (unsigned long)mod->module_core,

				   sechdrs[i].sh_size, GFP_KERNEL);

	}

}

#else

static inline void kmemleak_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 noinline struct module *load_module(void __user *umod,
@@ -2046,6 +2088,12 @@ static noinline struct module *load_module(void __user *umod, 


	/* 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) {

		err = -ENOMEM;

		goto free_percpu;
@@ -2054,6 +2102,13 @@ static noinline struct module *load_module(void __user *umod, 
	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) {

		err = -ENOMEM;

		goto free_core;
@@ -2084,6 +2139,7 @@ static noinline struct module *load_module(void __user *umod, 
	}

	/* Module has been moved. */

	mod = (void *)sechdrs[modindex].sh_addr;

	kmemleak_load_module(mod, hdr, sechdrs, secstrings);



#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)

	mod->refptr = percpu_modalloc(sizeof(local_t), __alignof__(local_t),