diff options
author | Tejun Heo <tj@kernel.org> | 2012-10-18 17:52:07 -0700 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-28 10:56:14 -0700 |
commit | 04900efcfcd89fd11302748bbe88659d12fd7fb5 (patch) | |
tree | dfc42bf26f79c54d8bd9c9b86b0cd98fff8f664f /kernel/exit.c | |
parent | b4cd7aa6602e17f7c128ddf0c9b0dc7b4e2b897c (diff) |
Revert "cgroup: Drop task_lock(parent) on cgroup_fork()"
commit 9bb71308b8133d643648776243e4d5599b1c193d upstream.
This reverts commit 7e381b0eb1e1a9805c37335562e8dc02e7d7848c.
The commit incorrectly assumed that fork path always performed
threadgroup_change_begin/end() and depended on that for
synchronization against task exit and cgroup migration paths instead
of explicitly grabbing task_lock().
threadgroup_change is not locked when forking a new process (as
opposed to a new thread in the same process) and even if it were it
wouldn't be effective as different processes use different threadgroup
locks.
Revert the incorrect optimization.
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <20121008020000.GB2575@localhost>
Acked-by: Li Zefan <lizefan@huawei.com>
Bitterly-Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/exit.c')
0 files changed, 0 insertions, 0 deletions