On Wed, Oct 09, 2019 at 05:02:30PM +0200, Oleg Nesterov wrote:
> ptrace_stop() does preempt_enable_no_resched() to avoid the preemption,
> but after that cgroup_enter_frozen() does spin_lock/unlock and this adds
> another preemption point.
>
> Reported-and-tested-by: Bruce Ashfield <bruce.ashfi...@gmail.com>
> Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer")
> Cc: sta...@vger.kernel.org # v5.2+
> Signed-off-by: Oleg Nesterov <o...@redhat.com>Applied to cgroup/for-5.4-fixes. Thanks. -- tejun
