[patch 02/14] fork, memcg: fix cached_stacks case

[patch 02/14] fork, memcg: fix cached_stacks case

[akpm]

From: Shakeel Butt <shakeelb@google.com>
Subject: fork, memcg: fix cached_stacks case

5eed6f1dff87 ("fork,memcg: fix crash in free_thread_stack on memcg charge
fail") fixes a crash caused due to failed memcg charge of the kernel
stack.  However the fix misses the cached_stacks case which this patch
fixes.  So, the same crash can happen if the memcg charge of a cached
stack is failed.

Link: http://lkml.kernel.org/r/20190102180145.57406-1-shakeelb@google.com
Fixes: 5eed6f1dff87 ("fork,memcg: fix crash in free_thread_stack on memcg charge fail")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/fork.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/fork.c~fork-memcg-fix-cached_stacks-case
+++ a/kernel/fork.c
@@ -217,6 +217,7 @@ static unsigned long *alloc_thread_stack
 		memset(s->addr, 0, THREAD_SIZE);
 
 		tsk->stack_vm_area = s;
+		tsk->stack = s->addr;
 		return s->addr;
 	}
 
_