From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966864AbbLPRl0 (ORCPT ); Wed, 16 Dec 2015 12:41:26 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:50247 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966775AbbLPRlU (ORCPT ); Wed, 16 Dec 2015 12:41:20 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Peter Zijlstra (Intel)" , Linus Torvalds , Mike Galbraith , Thomas Gleixner , mark.rutland@arm.com, neilb@suse.de, oleg@redhat.com, Ingo Molnar , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 128/128] sched/wait: Fix signal handling in bit wait helpers Date: Wed, 16 Dec 2015 09:39:28 -0800 Message-Id: <1450287568-19808-129-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1450287568-19808-1-git-send-email-kamal@canonical.com> References: <1450287568-19808-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt12 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 68985633bccb6066bf1803e316fbc6c1f5b796d6 upstream. Vladimir reported getting RCU stall warnings and bisected it back to commit: 743162013d40 ("sched: Remove proliferation of wait_on_bit() action functions") That commit inadvertently reversed the calls to schedule() and signal_pending(), thereby not handling the case where the signal receives while we sleep. Reported-by: Vladimir Murzin Tested-by: Vladimir Murzin Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: mark.rutland@arm.com Cc: neilb@suse.de Cc: oleg@redhat.com Fixes: 743162013d40 ("sched: Remove proliferation of wait_on_bit() action functions") Fixes: cbbce8220949 ("SCHED: add some "wait..on_bit...timeout()" interfaces.") Link: http://lkml.kernel.org/r/20151201130404.GL3816@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Kamal Mostafa --- kernel/sched/wait.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 852143a..e0bb7e6 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -583,18 +583,18 @@ EXPORT_SYMBOL(wake_up_atomic_t); __sched int bit_wait(struct wait_bit_key *word) { - if (signal_pending_state(current->state, current)) - return 1; schedule(); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL(bit_wait); __sched int bit_wait_io(struct wait_bit_key *word) { - if (signal_pending_state(current->state, current)) - return 1; io_schedule(); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL(bit_wait_io); @@ -602,11 +602,11 @@ EXPORT_SYMBOL(bit_wait_io); __sched int bit_wait_timeout(struct wait_bit_key *word) { unsigned long now = ACCESS_ONCE(jiffies); - if (signal_pending_state(current->state, current)) - return 1; if (time_after_eq(now, word->timeout)) return -EAGAIN; schedule_timeout(word->timeout - now); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL_GPL(bit_wait_timeout); @@ -614,11 +614,11 @@ EXPORT_SYMBOL_GPL(bit_wait_timeout); __sched int bit_wait_io_timeout(struct wait_bit_key *word) { unsigned long now = ACCESS_ONCE(jiffies); - if (signal_pending_state(current->state, current)) - return 1; if (time_after_eq(now, word->timeout)) return -EAGAIN; io_schedule_timeout(word->timeout - now); + if (signal_pending(current)) + return -EINTR; return 0; } EXPORT_SYMBOL_GPL(bit_wait_io_timeout); -- 1.9.1