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 6569BC35296 for ; Fri, 1 Apr 2022 15:40:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357469AbiDAPii (ORCPT ); Fri, 1 Apr 2022 11:38:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350672AbiDAPAZ (ORCPT ); Fri, 1 Apr 2022 11:00:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E80232FFC0; Fri, 1 Apr 2022 07:48:44 -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 82F0060C9B; Fri, 1 Apr 2022 14:48:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A551C2BBE4; Fri, 1 Apr 2022 14:48:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648824523; bh=VOQJl+M10hiXQCzmqGdvprLeFI05sGhBpUkds2yTKOc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T0XfFtO7Fmvy2mvagSRLptfwf6QOzRYoYhVrIS1dgft2M5W4aIUrTllV3+NeFjg3Z TXcsBb+31OVJo0xYNJONeqQ8iMDK5PHnURYmwvsJhAbJqEGAoNGhoKOcly9UgGJ0Cj bEVZ4UJ2sGxBW9Iz3Hl26CCsPYKixl5yfN22bu0WMMizYYMRg9dThcifCWDlOSYTlo hIUJOdaPKnTK/2SJXb/L8boIPIsG19TMkA51c4gb460gr2Vvx6pgIUhxOQfm6+iZSx 9LpeKPesyp5KYWIpXmbm+szSwR0R2BIABPsZggeBtNQmF5KlOq1kDbEtuT/yJVudWy OVLzufUgta1lg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zhou Guanghui , Will Deacon , Sasha Levin , joro@8bytes.org, iommu@lists.linux-foundation.org Subject: [PATCH AUTOSEL 4.9 06/16] iommu/arm-smmu-v3: fix event handling soft lockup Date: Fri, 1 Apr 2022 10:48:17 -0400 Message-Id: <20220401144827.1955845-6-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220401144827.1955845-1-sashal@kernel.org> References: <20220401144827.1955845-1-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: Zhou Guanghui [ Upstream commit 30de2b541af98179780054836b48825fcfba4408 ] During event processing, events are read from the event queue one by one until the queue is empty.If the master device continuously requests address access at the same time and the SMMU generates events, the cyclic processing of the event takes a long time and softlockup warnings may be reported. arm-smmu-v3 arm-smmu-v3.34.auto: event 0x0a received: arm-smmu-v3 arm-smmu-v3.34.auto: 0x00007f220000280a arm-smmu-v3 arm-smmu-v3.34.auto: 0x000010000000007e arm-smmu-v3 arm-smmu-v3.34.auto: 0x00000000034e8670 watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [irq/268-arm-smm:247] Call trace: _dev_info+0x7c/0xa0 arm_smmu_evtq_thread+0x1c0/0x230 irq_thread_fn+0x30/0x80 irq_thread+0x128/0x210 kthread+0x134/0x138 ret_from_fork+0x10/0x1c Kernel panic - not syncing: softlockup: hung tasks Fix this by calling cond_resched() after the event information is printed. Signed-off-by: Zhou Guanghui Link: https://lore.kernel.org/r/20220119070754.26528-1-zhouguanghui1@huawei.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/iommu/arm-smmu-v3.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 48d382008788..db40ce599e97 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -1171,6 +1171,7 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) dev_info(smmu->dev, "\t0x%016llx\n", (unsigned long long)evt[i]); + cond_resched(); } /* -- 2.34.1