From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933126AbcI3L5b (ORCPT ); Fri, 30 Sep 2016 07:57:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44674 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932252AbcI3L5Y (ORCPT ); Fri, 30 Sep 2016 07:57:24 -0400 Date: Fri, 30 Sep 2016 04:56:23 -0700 From: tip-bot for Oleg Nesterov Message-ID: Cc: bvanassche@acm.org, mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, neilb@suse.de, efault@gmx.de, torvalds@linux-foundation.org, viro@ZenIV.linux.org.uk, oleg@redhat.com, hannes@cmpxchg.org, peterz@infradead.org, tglx@linutronix.de Reply-To: hpa@zytor.com, mingo@kernel.org, bvanassche@acm.org, viro@ZenIV.linux.org.uk, torvalds@linux-foundation.org, efault@gmx.de, linux-kernel@vger.kernel.org, neilb@suse.de, hannes@cmpxchg.org, oleg@redhat.com, tglx@linutronix.de, peterz@infradead.org In-Reply-To: <20160906140047.GA6157@redhat.com> References: <20160906140047.GA6157@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/wait: Fix abort_exclusive_wait(), it should pass TASK_NORMAL to wake_up() Git-Commit-ID: 38a3e1fc1dac480f3672ab22fc97e1f995c80ed7 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 38a3e1fc1dac480f3672ab22fc97e1f995c80ed7 Gitweb: http://git.kernel.org/tip/38a3e1fc1dac480f3672ab22fc97e1f995c80ed7 Author: Oleg Nesterov AuthorDate: Tue, 6 Sep 2016 16:00:47 +0200 Committer: Ingo Molnar CommitDate: Fri, 30 Sep 2016 10:53:19 +0200 sched/wait: Fix abort_exclusive_wait(), it should pass TASK_NORMAL to wake_up() Otherwise this logic only works if mode is "compatible" with another exclusive waiter. If some wq has both TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE waiters, abort_exclusive_wait() won't wait an uninterruptible waiter. The main user is __wait_on_bit_lock() and currently it is fine but only because TASK_KILLABLE includes TASK_UNINTERRUPTIBLE and we do not have lock_page_interruptible() yet. Just use TASK_NORMAL and remove the "mode" arg from abort_exclusive_wait(). Yes, this means that (say) wake_up_interruptible() can wake up the non- interruptible waiter(s), but I think this is fine. And in fact I think that abort_exclusive_wait() must die, see the next change. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Al Viro Cc: Bart Van Assche Cc: Johannes Weiner Cc: Linus Torvalds Cc: Mike Galbraith Cc: Neil Brown Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20160906140047.GA6157@redhat.com Signed-off-by: Ingo Molnar --- include/linux/wait.h | 6 +++--- kernel/sched/wait.c | 8 +++----- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/include/linux/wait.h b/include/linux/wait.h index c3ff74d..e4cfd1e 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -281,8 +281,8 @@ wait_queue_head_t *bit_waitqueue(void *, int); if (___wait_is_interruptible(state) && __int) { \ __ret = __int; \ if (exclusive) { \ - abort_exclusive_wait(&wq, &__wait, \ - state, NULL); \ + abort_exclusive_wait(&wq, &__wait, \ + NULL); \ goto __out; \ } \ break; \ @@ -989,7 +989,7 @@ void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state); void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state); long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state); void finish_wait(wait_queue_head_t *q, wait_queue_t *wait); -void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key); +void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, void *key); long wait_woken(wait_queue_t *wait, unsigned mode, long timeout); int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key); int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key); diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index f15d6b6..2bbba01 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -259,7 +259,6 @@ EXPORT_SYMBOL(finish_wait); * abort_exclusive_wait - abort exclusive waiting in a queue * @q: waitqueue waited on * @wait: wait descriptor - * @mode: runstate of the waiter to be woken * @key: key to identify a wait bit queue or %NULL * * Sets current thread back to running state and removes @@ -273,8 +272,7 @@ EXPORT_SYMBOL(finish_wait); * aborts and is woken up concurrently and no one wakes up * the next waiter. */ -void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, - unsigned int mode, void *key) +void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, void *key) { unsigned long flags; @@ -283,7 +281,7 @@ void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, if (!list_empty(&wait->task_list)) list_del_init(&wait->task_list); else if (waitqueue_active(q)) - __wake_up_locked_key(q, mode, key); + __wake_up_locked_key(q, TASK_NORMAL, key); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(abort_exclusive_wait); @@ -434,7 +432,7 @@ __wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q, ret = action(&q->key, mode); if (!ret) continue; - abort_exclusive_wait(wq, &q->wait, mode, &q->key); + abort_exclusive_wait(wq, &q->wait, &q->key); return ret; } while (test_and_set_bit(q->key.bit_nr, q->key.flags)); finish_wait(wq, &q->wait);