tree 301d615747210733a271c376fc036a7480594207
parent d721304dce0ced0b3b0366996cc02929669708a8
author Oleg Nesterov <oleg@tv-sign.ru> 1178703248 -0700
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1178739052 -0700

workqueue: don't clear cwq->thread until it exits

Pointed out by Srivatsa Vaddagiri.

cleanup_workqueue_thread() sets cwq->thread = NULL and does kthread_stop().
This breaks the "if (cwq->thread == current)" logic in flush_cpu_workqueue()
and leads to deadlock.

Kill the thead first, then clear cwq->thread. workqueue_mutex protects us
from create_workqueue_thread() so we don't need cwq->lock.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Gautham shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>