Re: [PATCH v2 1/3] cgroup: Iterate tasks that did not finish do_exit()
From: Tejun Heo <tj@kernel.org>
Date: 2020-02-12 22:03:10
Also in:
cgroups, linux-kselftest, linux-mediatek, lkml
On Fri, Jan 24, 2020 at 12:40:15PM +0100, Michal Koutný wrote:
PF_EXITING is set earlier than actual removal from css_set when a task
is exitting. This can confuse cgroup.procs readers who see no PF_EXITING
tasks, however, rmdir is checking against css_set membership so it can
transitionally fail with EBUSY.
Fix this by listing tasks that weren't unlinked from css_set active
lists.
It may happen that other users of the task iterator (without
CSS_TASK_ITER_PROCS) spot a PF_EXITING task before cgroup_exit(). This
is equal to the state before commit c03cd7738a83 ("cgroup: Include dying
leaders with live threads in PROCS iterations") but it may be reviewed
later.
Reported-by: Suren Baghdasaryan <surenb@google.com>
Fixes: c03cd7738a83 ("cgroup: Include dying leaders with live threads in PROCS iterations")
Signed-off-by: Michal Koutný <mkoutny@suse.com>Applied to cgroup/for-5.6-fixes. Thanks. -- tejun _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel