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authorDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>2012-10-04 09:37:16 +0200
committerTejun Heo <tj@kernel.org>2012-10-17 02:09:36 +0200
commit1f5320d5972aa50d3e8d2b227b636b370e608359 (patch)
treea36f1ef6a2f2f72d81e5aef43c0089bb62056bf5
parentLinux 3.7-rc1 (diff)
downloadlinux-1f5320d5972aa50d3e8d2b227b636b370e608359.tar.xz
linux-1f5320d5972aa50d3e8d2b227b636b370e608359.zip
cgroup: notify_on_release may not be triggered in some cases
notify_on_release must be triggered when the last process in a cgroup is move to another. But if the first(and only) process in a cgroup is moved to another, notify_on_release is not triggered. # mkdir /cgroup/cpu/SRC # mkdir /cgroup/cpu/DST # # echo 1 >/cgroup/cpu/SRC/notify_on_release # echo 1 >/cgroup/cpu/DST/notify_on_release # # sleep 300 & [1] 8629 # # echo 8629 >/cgroup/cpu/SRC/tasks # echo 8629 >/cgroup/cpu/DST/tasks -> notify_on_release for /SRC must be triggered at this point, but it isn't. This is because put_css_set() is called before setting CGRP_RELEASABLE in cgroup_task_migrate(), and is a regression introduce by the commit:74a1166d(cgroups: make procs file writable), which was merged into v3.0. Cc: Ben Blum <bblum@andrew.cmu.edu> Cc: <stable@vger.kernel.org> # v3.0.x and later Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r--kernel/cgroup.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 13774b3b39aa..d1739fc7eb94 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1962,9 +1962,8 @@ static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp,
* trading it for newcg is protected by cgroup_mutex, we're safe to drop
* it here; it will be freed under RCU.
*/
- put_css_set(oldcg);
-
set_bit(CGRP_RELEASABLE, &oldcgrp->flags);
+ put_css_set(oldcg);
}
/**