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authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2017-10-13 15:58:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-10-13 16:18:33 -0700
commitca182551857cc2c1e6a2b7f1e72090a137a15008 (patch)
tree2811f50f3d352d6f82f453e05a76489637b2d1b0
parent7e86600606cef21beec725039d70377fb364f881 (diff)
downloadlinux-sh-ca182551857cc2c1e6a2b7f1e72090a137a15008.tar.gz
kmemleak: clear stale pointers from task stacks
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>
-rw-r--r--include/linux/thread_info.h2
-rw-r--r--kernel/fork.c4
2 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 905d769d8ddc..5f7eeab990fe 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -42,7 +42,7 @@ enum {
#define THREAD_ALIGN THREAD_SIZE
#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 | \
__GFP_ZERO)
#else
diff --git a/kernel/fork.c b/kernel/fork.c
index e702cb9ffbd8..07cc743698d3 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -215,6 +215,10 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
if (!s)
continue;
+#ifdef CONFIG_DEBUG_KMEMLEAK
+ /* Clear stale pointers from reused stack. */
+ memset(s->addr, 0, THREAD_SIZE);
+#endif
tsk->stack_vm_area = s;
return s->addr;
}