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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65A0DC32772 for ; Tue, 23 Aug 2022 11:17:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357337AbiHWLP3 (ORCPT ); Tue, 23 Aug 2022 07:15:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242344AbiHWLOt (ORCPT ); Tue, 23 Aug 2022 07:14:49 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3390A895D3; Tue, 23 Aug 2022 02:18:49 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B60DF61224; Tue, 23 Aug 2022 09:17:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDCB1C433D6; Tue, 23 Aug 2022 09:17:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661246276; bh=woNk0l7ptzPOFYbS0hhw1ok9LRQolQhlhYXUOEC+PK0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nfswBzAeyHFN0kuke8D+74oLXw3cjw5bimLts0Lsz+MQVv96rSoCZ0MeI8q2kd/D1 Kd7O33Gik73SPhBAmPN/gFv5tCFw3ZFuz6ULrZj/MJBlCJwF5utV7PYFGGvY6M268T Q3IHue2IWC8+Xsds/zBAdKQg5D/nXiCQ6sIa9KBw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bruno Goncalves , Juri Lelli , Thomas Gleixner , Daniel Bristot de Oliveira , Valentin Schneider , Sasha Levin Subject: [PATCH 5.4 057/389] wait: Fix __wait_event_hrtimeout for RT/DL tasks Date: Tue, 23 Aug 2022 10:22:15 +0200 Message-Id: <20220823080117.986098453@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080115.331990024@linuxfoundation.org> References: <20220823080115.331990024@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Juri Lelli [ Upstream commit cceeeb6a6d02e7b9a74ddd27a3225013b34174aa ] Changes to hrtimer mode (potentially made by __hrtimer_init_sleeper on PREEMPT_RT) are not visible to hrtimer_start_range_ns, thus not accounted for by hrtimer_start_expires call paths. In particular, __wait_event_hrtimeout suffers from this problem as we have, for example: fs/aio.c::read_events wait_event_interruptible_hrtimeout __wait_event_hrtimeout hrtimer_init_sleeper_on_stack <- this might "mode |= HRTIMER_MODE_HARD" on RT if task runs at RT/DL priority hrtimer_start_range_ns WARN_ON_ONCE(!(mode & HRTIMER_MODE_HARD) ^ !timer->is_hard) fires since the latter doesn't see the change of mode done by init_sleeper Fix it by making __wait_event_hrtimeout call hrtimer_sleeper_start_expires, which is aware of the special RT/DL case, instead of hrtimer_start_range_ns. Reported-by: Bruno Goncalves Signed-off-by: Juri Lelli Signed-off-by: Thomas Gleixner Reviewed-by: Daniel Bristot de Oliveira Reviewed-by: Valentin Schneider Link: https://lore.kernel.org/r/20220627095051.42470-1-juri.lelli@redhat.com Signed-off-by: Sasha Levin --- include/linux/wait.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/include/linux/wait.h b/include/linux/wait.h index 5903b1d17c92..7d04c1b588c7 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -529,10 +529,11 @@ do { \ \ hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC, \ HRTIMER_MODE_REL); \ - if ((timeout) != KTIME_MAX) \ - hrtimer_start_range_ns(&__t.timer, timeout, \ - current->timer_slack_ns, \ - HRTIMER_MODE_REL); \ + if ((timeout) != KTIME_MAX) { \ + hrtimer_set_expires_range_ns(&__t.timer, timeout, \ + current->timer_slack_ns); \ + hrtimer_sleeper_start_expires(&__t, HRTIMER_MODE_REL); \ + } \ \ __ret = ___wait_event(wq_head, condition, state, 0, 0, \ if (!__t.task) { \ -- 2.35.1