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kmemleak: clear stale pointers from task stacks

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Kmemleak considers any pointers on task stacks as references.  This
patch clears newly allocated and reused vmap stacks.

Link: http://lkml.kernel.org/r/150728990124.744199.8403409836394318684.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Konstantin Khlebnikov 2017-10-13 15:58:22 -07:00 committed by Linus Torvalds
parent 7e86600606
commit ca18255185
2 changed files with 5 additions and 1 deletions
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2
include/linux/thread_info.h
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@ -42,7 +42,7 @@ enum {
#define THREAD_ALIGN THREAD_SIZE #define THREAD_ALIGN THREAD_SIZE
#endif #endif
#ifdef CONFIG_DEBUG_STACK_USAGE #if IS_ENABLED(CONFIG_DEBUG_STACK_USAGE) || IS_ENABLED(CONFIG_DEBUG_KMEMLEAK)
# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \ # define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \
__GFP_ZERO) __GFP_ZERO)
#else #else

4
kernel/fork.c
View file

@ -215,6 +215,10 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
if (!s) if (!s)
continue; continue;
#ifdef CONFIG_DEBUG_KMEMLEAK
/* Clear stale pointers from reused stack. */
memset(s->addr, 0, THREAD_SIZE);
#endif
tsk->stack_vm_area = s; tsk->stack_vm_area = s;
return s->addr; return s->addr;
} }