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| author | Mandeep Singh Baines <msb@chromium.org> | 2011-12-15 11:36:43 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-06 14:13:53 -0800 |
| commit | b05727c7f8e3b30309d013a7d3bbc6d1e6f860ba (patch) | |
| tree | e50ad4a59ee25b1b79a099ba2fbf510865439f17 /kernel/cgroup.c | |
| parent | 2aad1ca4711a46ca4540c924ffb84e7673a4738c (diff) | |
| download | kernel_samsung_smdk4412-b05727c7f8e3b30309d013a7d3bbc6d1e6f860ba.zip kernel_samsung_smdk4412-b05727c7f8e3b30309d013a7d3bbc6d1e6f860ba.tar.gz kernel_samsung_smdk4412-b05727c7f8e3b30309d013a7d3bbc6d1e6f860ba.tar.bz2 | |
cgroups: fix a css_set not found bug in cgroup_attach_proc
commit e0197aae59e55c06db172bfbe1a1cdb8c0e1cab3 upstream.
There is a BUG when migrating a PF_EXITING proc. Since css_set_prefetch()
is not called for the PF_EXITING case, find_existing_css_set() will return
NULL inside cgroup_task_migrate() causing a BUG.
This bug is easy to reproduce. Create a zombie and echo its pid to
cgroup.procs.
$ cat zombie.c
\#include <unistd.h>
int main()
{
if (fork())
pause();
return 0;
}
$
We are hitting this bug pretty regularly on ChromeOS.
This bug is already fixed by Tejun Heo's cgroup patchset which is
targetted for the next merge window:
https://lkml.org/lkml/2011/11/1/356
I've create a smaller patch here which just fixes this bug so that a
fix can be merged into the current release and stable.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Downstream-Bug-Report: http://crosbug.com/23953
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: containers@lists.linux-foundation.org
Cc: cgroups@vger.kernel.org
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Menage <paul@paulmenage.org>
Cc: Olof Johansson <olofj@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 2731d11..575a5e7 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2095,11 +2095,6 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) continue; /* get old css_set pointer */ task_lock(tsk); - if (tsk->flags & PF_EXITING) { - /* ignore this task if it's going away */ - task_unlock(tsk); - continue; - } oldcg = tsk->cgroups; get_css_set(oldcg); task_unlock(tsk); |