* [PATCH] kmemleak: clear stale pointers from task stacks
@ 2017-10-06 11:38 Konstantin Khlebnikov
2017-10-06 14:02 ` Catalin Marinas
0 siblings, 1 reply; 2+ messages in thread
From: Konstantin Khlebnikov @ 2017-10-06 11:38 UTC (permalink / raw)
To: linux-mm, Andrew Morton, linux-kernel, Catalin Marinas; +Cc: Andy Lutomirski
Kmemleak considers any pointers as task stacks as references.
This patch clears newly allocated and reused vmap stacks.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
include/linux/thread_info.h | 2 +-
kernel/fork.c | 4 ++++
2 files changed, 5 insertions(+), 1 deletion(-)
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 c4ff0303b7c5..53e3b6f8a3bf 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -213,6 +213,10 @@ 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;
}
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] kmemleak: clear stale pointers from task stacks
2017-10-06 11:38 [PATCH] kmemleak: clear stale pointers from task stacks Konstantin Khlebnikov
@ 2017-10-06 14:02 ` Catalin Marinas
0 siblings, 0 replies; 2+ messages in thread
From: Catalin Marinas @ 2017-10-06 14:02 UTC (permalink / raw)
To: Konstantin Khlebnikov
Cc: linux-mm, Andrew Morton, linux-kernel, Andy Lutomirski
On Fri, Oct 06, 2017 at 02:38:21PM +0300, Konstantin Khlebnikov wrote:
> Kmemleak considers any pointers as task stacks as references.
^^
on
> This patch clears newly allocated and reused vmap stacks.
>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
> ---
> include/linux/thread_info.h | 2 +-
> kernel/fork.c | 4 ++++
> 2 files changed, 5 insertions(+), 1 deletion(-)
>
> 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 c4ff0303b7c5..53e3b6f8a3bf 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -213,6 +213,10 @@ 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;
> }
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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2017-10-06 14:02 ` Catalin Marinas
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