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kmemleak: clear stale pointers from task stacks

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commit ca182551857cc2c1e6a2b7f1e72090a137a15008 upstream.

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>
[ Srivatsa: Backported to 4.9.y ]
Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Konstantin Khlebnikov 2017-10-13 15:58:22 -07:00 committed by Greg Kroah-Hartman
parent 36ee106e84
commit 885b49b4f3
2 changed files with 5 additions and 1 deletions
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2
include/linux/thread_info.h
View File

@ -59,7 +59,7 @@ extern long do_no_restart_syscall(struct restart_block *parm);
#ifdef __KERNEL__
#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 | \
__GFP_ZERO)
#else

4
kernel/fork.c
View File

@ -184,6 +184,10 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
continue;
this_cpu_write(cached_stacks[i], NULL);
#ifdef CONFIG_DEBUG_KMEMLEAK
/* Clear stale pointers from reused stack. */
memset(s->addr, 0, THREAD_SIZE);
#endif
tsk->stack_vm_area = s;
local_irq_enable();
return s->addr;