Revert "cgroup: Remove task_lock() from cgroup_post_fork()"
This reverts commit 7e3aa30ac8c904a706518b725c451bb486daaae9.
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
Revert the incorrect optimization.
Signed-off-by: Tejun Heo <firstname.lastname@example.org>
Acked-by: Li Zefan <email@example.com>
Cc: Frederic Weisbecker <firstname.lastname@example.org>
1 file changed