From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4CA4C28CF6 for ; Wed, 1 Aug 2018 17:21:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6796A20862 for ; Wed, 1 Aug 2018 17:21:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6796A20862 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390286AbeHATHj (ORCPT ); Wed, 1 Aug 2018 15:07:39 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49234 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389699AbeHATHi (ORCPT ); Wed, 1 Aug 2018 15:07:38 -0400 Received: from localhost (D57E6652.static.ziggozakelijk.nl [213.126.102.82]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 9D5F1CC2; Wed, 1 Aug 2018 17:20:56 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sebastian Andrzej Siewior , Thomas Gleixner , Balbir Singh , Sasha Levin Subject: [PATCH 4.14 182/246] delayacct: Use raw_spinlocks Date: Wed, 1 Aug 2018 18:51:32 +0200 Message-Id: <20180801165020.433413561@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180801165011.700991984@linuxfoundation.org> References: <20180801165011.700991984@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior [ Upstream commit 02acc80d19edb0d5684c997b2004ad19f9f5236e ] try_to_wake_up() might invoke delayacct_blkio_end() while holding the pi_lock (which is a raw_spinlock_t). delayacct_blkio_end() acquires task_delay_info.lock which is a spinlock_t. This causes a might sleep splat on -RT where non raw spinlocks are converted to 'sleeping' spinlocks. task_delay_info.lock is only held for a short amount of time so it's not a problem latency wise to make convert it to a raw spinlock. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Balbir Singh Link: https://lkml.kernel.org/r/20180423161024.6710-1-bigeasy@linutronix.de Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/linux/delayacct.h | 2 +- kernel/delayacct.c | 17 +++++++++-------- 2 files changed, 10 insertions(+), 9 deletions(-) --- a/include/linux/delayacct.h +++ b/include/linux/delayacct.h @@ -29,7 +29,7 @@ #ifdef CONFIG_TASK_DELAY_ACCT struct task_delay_info { - spinlock_t lock; + raw_spinlock_t lock; unsigned int flags; /* Private per-task flags */ /* For each stat XXX, add following, aligned appropriately --- a/kernel/delayacct.c +++ b/kernel/delayacct.c @@ -44,23 +44,24 @@ void __delayacct_tsk_init(struct task_st { tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL); if (tsk->delays) - spin_lock_init(&tsk->delays->lock); + raw_spin_lock_init(&tsk->delays->lock); } /* * Finish delay accounting for a statistic using its timestamps (@start), * accumalator (@total) and @count */ -static void delayacct_end(spinlock_t *lock, u64 *start, u64 *total, u32 *count) +static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, + u32 *count) { s64 ns = ktime_get_ns() - *start; unsigned long flags; if (ns > 0) { - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); *total += ns; (*count)++; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); } } @@ -127,7 +128,7 @@ int __delayacct_add_tsk(struct taskstats /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ - spin_lock_irqsave(&tsk->delays->lock, flags); + raw_spin_lock_irqsave(&tsk->delays->lock, flags); tmp = d->blkio_delay_total + tsk->delays->blkio_delay; d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; tmp = d->swapin_delay_total + tsk->delays->swapin_delay; @@ -137,7 +138,7 @@ int __delayacct_add_tsk(struct taskstats d->blkio_count += tsk->delays->blkio_count; d->swapin_count += tsk->delays->swapin_count; d->freepages_count += tsk->delays->freepages_count; - spin_unlock_irqrestore(&tsk->delays->lock, flags); + raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); return 0; } @@ -147,10 +148,10 @@ __u64 __delayacct_blkio_ticks(struct tas __u64 ret; unsigned long flags; - spin_lock_irqsave(&tsk->delays->lock, flags); + raw_spin_lock_irqsave(&tsk->delays->lock, flags); ret = nsec_to_clock_t(tsk->delays->blkio_delay + tsk->delays->swapin_delay); - spin_unlock_irqrestore(&tsk->delays->lock, flags); + raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); return ret; }