On 04/25, Frederic Weisbecker wrote:
>
> This reverts commit 28319d6dc5e2ffefa452c2377dd0f71621b5bff0. The race
> it fixed was subject to conditions that don't exist anymore since:
>
> 1612160b9127 ("rcu-tasks: Eliminate deadlocks involving do_exit() and RCU tasks")
>
> This latter commit removes the use of SRCU that used to cover the
> RCU-tasks blind spot on exit between the tasklist's removal and the
> final preemption disabling. The task is now placed instead into a
> temporary list inside which voluntary sleeps are accounted as RCU-tasks
> quiescent states. This would disarm the deadlock initially reported
> against PID namespace exit.
>
> Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
> ---
> include/linux/rcupdate.h | 2 --
> kernel/pid_namespace.c | 17 -----------------
> kernel/rcu/tasks.h | 16 +++-------------
> 3 files changed, 3 insertions(+), 32 deletions(-)
LGTM. FWIW,
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
