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authorWaiman Long <longman@redhat.com>2017-05-15 09:34:06 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-14 15:06:00 +0200
commitdff4c8bb1397337bc7663447d7f6ccbb3a52f8d9 (patch)
treefd113b4a4a7b326a13f38ee4d24b598e634e426b /kernel
parentb59ec7072c84c09461d98376a3358879d0034098 (diff)
cgroup: Prevent kill_css() from being called more than once
commit 33c35aa4817864e056fd772230b0c6b552e36ea2 upstream. The kill_css() function may be called more than once under the condition that the css was killed but not physically removed yet followed by the removal of the cgroup that is hosting the css. This patch prevents any harmm from being done when that happens. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a3d2aad2443f..1fde8eec9529 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5407,6 +5407,11 @@ static void kill_css(struct cgroup_subsys_state *css)
{
lockdep_assert_held(&cgroup_mutex);
+ if (css->flags & CSS_DYING)
+ return;
+
+ css->flags |= CSS_DYING;
+
/*
* This must happen before css is disassociated with its cgroup.
* See seq_css() for details.