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Commit 885b49b4 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Greg Kroah-Hartman
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kmemleak: clear stale pointers from task stacks 

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: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
[ Srivatsa: Backported to 4.9.y ]
Signed-off-by: default avatarSrivatsa S. Bhat <srivatsa@csail.mit.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 36ee106e

include/linux/thread_info.h

+1 −1
Original line number Diff line number Diff line
@@ -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

kernel/fork.c

+4 −0
Original line number Diff line number Diff line
@@ -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;