sched/autogroup: Do not use autogroup->tg in zombie threads
authorOleg Nesterov <oleg@redhat.com>
Mon, 14 Nov 2016 18:46:12 +0000 (19:46 +0100)
committerIngo Molnar <mingo@kernel.org>
Tue, 22 Nov 2016 11:33:43 +0000 (12:33 +0100)
commit8e5bfa8c1f8471aa4a2d30be631ef2b50e10abaf
treead3d1c2dc3f1770ac865c8f1df91a53c1e276728
parent18f649ef344127ef6de23a5a4272dbe2fdb73dde
sched/autogroup: Do not use autogroup->tg in zombie threads

Exactly because for_each_thread() in autogroup_move_group() can't see it
and update its ->sched_task_group before _put() and possibly free().

So the exiting task needs another sched_move_task() before exit_notify()
and we need to re-introduce the PF_EXITING (or similar) check removed by
the previous change for another reason.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hartsjc@redhat.com
Cc: vbendel@redhat.com
Cc: vlovejoy@redhat.com
Link: http://lkml.kernel.org/r/20161114184612.GA15968@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
include/linux/sched.h
kernel/exit.c
kernel/sched/auto_group.c