Messages in this thread Patch in this message | | | Date | Thu, 4 Oct 2012 16:37:16 +0900 | From | Daisuke Nishimura <> | Subject | [REGRESSION] cgroup: notify_on_release may not be triggered in some cases |
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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: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: <stable@vger.kernel.org> # v3.0.x and later Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> --- This patch is based on v3.6.
kernel/cgroup.c | 3 +-- 1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 7981850..7d01182 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1923,9 +1923,8 @@ 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); } /** -- 1.7.1
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