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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 8C3BEC4332B for ; Thu, 19 Mar 2020 20:12:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EED0206D7 for ; Thu, 19 Mar 2020 20:12:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TwydsAJj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727259AbgCSUMl (ORCPT ); Thu, 19 Mar 2020 16:12:41 -0400 Received: from mail-lj1-f195.google.com ([209.85.208.195]:35024 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727183AbgCSUMi (ORCPT ); Thu, 19 Mar 2020 16:12:38 -0400 Received: by mail-lj1-f195.google.com with SMTP id u12so4036229ljo.2; Thu, 19 Mar 2020 13:12:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=wkLX2s1nqC4/s2saqipeX2z/4ELPxY+SBvbFqtjm2hU=; b=TwydsAJj8fSLn1Uj3o2Haivq/oiV2I2M1hW88D/4YfUQq559qApPr/vx91lKXFlRgy uHBz9/vM5/FYTdnQ71kEZksPThe0VMRZ9ciUuQ/3Iua8Of4BubAkPcHsVbUPqg9gHwUP KWIo2HXFGuoD6hxCOtU8S5C0ZDUkSEknTl61QzUl5obvo/sjgLBUVorEGADx95ICPssc Z6As6Y7spouFWqt93csCiGhD/SInV/g27n2gZEhNfZewJYX5mqsB7UrHsfmvSImzp5O5 0A0LY3Vs7Fbl4edAWwTbJbVUKfmuvVZwqafLAOjM73wW0GzTP2tceZTu3ZoesttbJQ0T z61A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=wkLX2s1nqC4/s2saqipeX2z/4ELPxY+SBvbFqtjm2hU=; b=Vr5xGtXMkPhuPWoIGgtgy6KwHhHjQhvtCPFLNWYOHvfmwzKrPBphTk/hudc1rTjzpR zqMNavfmgFIPxL9t6tdcb2WfzsbhV6/pQOhwZXGokn54cYHJIEZScUcJnN2nnbd/OrD4 fnKudblsjmkza6k1bdiQlv2/teJKZavBB/JSnvCPd6PqjyUsw5j4kLtYeKtvmgAg2o4V cRdYYMPWbhXTGpDybv6nW3XizrCDh1IzyqGfs9+r1QbC+HXKmFslwFqzvWxphy9ReNG4 s6P8N741YUfEVYAQ8G8sIkxFXhpl+X03y6fva0Km62UXcscGNz9h5Ph58cFDOvUDRhwf yA/w== X-Gm-Message-State: ANhLgQ3o2m0d0sG0QWlDXUrHQY7HOK7GeCSekW3cp7lwyxN1ZJphoRJo gBMR2MFrJ2lX5UlQIarP4co= X-Google-Smtp-Source: ADFU+vsJ1IvYqKOAsalgCu/GNkuLPf8EfUK4hU2fz7zgktmlhFHKLUClSRydu3/ewT8BvJgwFzZ6DA== X-Received: by 2002:a2e:b4e5:: with SMTP id s5mr3240453ljm.190.1584648756385; Thu, 19 Mar 2020 13:12:36 -0700 (PDT) Received: from localhost.localdomain (94-29-39-224.dynamic.spd-mgts.ru. [94.29.39.224]) by smtp.gmail.com with ESMTPSA id z21sm2059317ljz.49.2020.03.19.13.12.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Mar 2020 13:12:35 -0700 (PDT) From: Dmitry Osipenko To: Thierry Reding , Jonathan Hunter , Laxman Dewangan , Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org, Vinod Koul , Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v1 1/2] i2c: tegra: Better handle case where CPU0 is busy for a long time Date: Thu, 19 Mar 2020 23:11:39 +0300 Message-Id: <20200319201140.17451-2-digetx@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200319201140.17451-1-digetx@gmail.com> References: <20200319201140.17451-1-digetx@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Boot CPU0 always handle I2C interrupt and under some rare circumstances (like running KASAN + NFS root) it may stuck in uninterruptible state for a significant time. In this case we will get timeout if I2C transfer is running on a sibling CPU, despite of IRQ being raised. In order to handle this rare condition, the IRQ status needs to be checked after completion timeout. Signed-off-by: Dmitry Osipenko --- drivers/i2c/busses/i2c-tegra.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index cbc2ad49043e..dabb9223990c 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -1034,14 +1034,18 @@ tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev, disable_irq(i2c_dev->irq); /* - * There is a chance that completion may happen after IRQ - * synchronization, which is done by disable_irq(). + * Under some rare circumstances (like running KASAN + + * NFS root) CPU, which handles interrupt, may stuck in + * uninterruptible state for a significant time. In this + * case we will get timeout if I2C transfer is running on + * a sibling CPU, despite of IRQ being raised. + * + * In order to handle this rare condition, the IRQ status + * needs to be checked after timeout. */ - if (ret == 0 && completion_done(complete)) { - dev_warn(i2c_dev->dev, - "completion done after timeout\n"); - ret = 1; - } + if (ret == 0) + ret = tegra_i2c_poll_completion_timeout(i2c_dev, + complete, 0); } return ret; -- 2.25.1