[PATCH] fork, memcg: fix cached_stacks case

* [PATCH] fork, memcg: fix cached_stacks case
@ 2019-01-02 18:01 Shakeel Butt
  2019-01-02 20:23 ` Michal Hocko
  2019-01-04 20:14 ` Rik van Riel
  0 siblings, 2 replies; 3+ messages in thread
From: Shakeel Butt @ 2019-01-02 18:01 UTC (permalink / raw)
  To: Rik van Riel, Roman Gushchin, Michal Hocko, Andrew Morton
  Cc: linux-mm, cgroups, linux-kernel, Shakeel Butt, Johannes Weiner,
	Tejun Heo, stable

Commit 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.

Fixes: 5eed6f1dff87 ("fork,memcg: fix crash in free_thread_stack on memcg charge fail")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
---
 kernel/fork.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/fork.c b/kernel/fork.c
index e4a51124661a..593cd1577dff 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -216,6 +216,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
 		memset(s->addr, 0, THREAD_SIZE);
 
 		tsk->stack_vm_area = s;
+		tsk->stack = s->addr;
 		return s->addr;
 	}
 
-- 
2.20.1.415.g653613c723-goog


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