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 8946EC19F2A for ; Mon, 8 Aug 2022 01:53:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243465AbiHHBxc (ORCPT ); Sun, 7 Aug 2022 21:53:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243444AbiHHBu6 (ORCPT ); Sun, 7 Aug 2022 21:50:58 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC17219036; Sun, 7 Aug 2022 18:38:01 -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 ams.source.kernel.org (Postfix) with ESMTPS id 05586B80E15; Mon, 8 Aug 2022 01:38:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1027C433C1; Mon, 8 Aug 2022 01:37:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659922678; bh=wBzxCo5hjBfe1zfh5zUb0PYm7nf2Nm7lHu2UY3R1mFU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uuiIAE3eWwzsm+q5X/rVRo5RMLa5jxe8ia4CK9ishywdKcsJb3AUVMb+DJrDH8z6S 6skFRfAOUzzxEFmj/SRBD9smJxLq8YzofMOnLbmSDDEdagigJ+dd7dGsXNJ17ndtfM fG1J1cJDXOYrptcNaV71Ny9U+CCZUXVu2w7netJOnSHwYOtktkGf/lwBlU7nXkFZ1J xrT5JSJuG0UMBtAbhdiEjO4IdWsP50act0uuseJTuYP4gcsffubcHhuUVUlSvjBKje IOpsj/7n35IhLs5e7swg3IXEPzKGgv3fml28m9tLcCbADXXraI1xIW2Ez+cZgz+XfD dwu9Anlbjf+iw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Juri Lelli , Bruno Goncalves , Thomas Gleixner , Daniel Bristot de Oliveira , Valentin Schneider , Sasha Levin , mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org Subject: [PATCH AUTOSEL 5.10 09/29] wait: Fix __wait_event_hrtimeout for RT/DL tasks Date: Sun, 7 Aug 2022 21:37:19 -0400 Message-Id: <20220808013741.316026-9-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220808013741.316026-1-sashal@kernel.org> References: <20220808013741.316026-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 9b8b0833100a..1663e47681a3 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -534,10 +534,11 @@ 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