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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 13A48C43463 for ; Fri, 18 Sep 2020 02:13:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF9C3239D4 for ; Fri, 18 Sep 2020 02:13:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395182; bh=IYgW8OLb/zFdIVzPPnLWfOpXT3c9vVAyrn9uipSSn7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RIjqQ3vsCnQQ5h3v+naPgSMOGD202PuBHMFd9eayBZllGzVvV1RyJYH8lHNjcOgQ2 zjEZQqt0rILPHndAAQ9LLQEBV1pc62eitf+MPzC9Tp/Sr1xPoFVqRsP6G/oLrB8rQj IwH7qTidQuBa7D6EshSc/euUi1Q2egFjy2HZJ5XI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728866AbgIRCNB (ORCPT ); Thu, 17 Sep 2020 22:13:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:39696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728846AbgIRCM4 (ORCPT ); Thu, 17 Sep 2020 22:12:56 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C3E4523447; Fri, 18 Sep 2020 02:12:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395175; bh=IYgW8OLb/zFdIVzPPnLWfOpXT3c9vVAyrn9uipSSn7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i4EZBL5BTufdV5u2KYVKR0Kjy32JqjzWZRclOwyn5oUhtzcF4CWU5Es2aiLGZ2h4v qfq6g6JvaIlRwrscXS/lbNBkKiGS7HNztbCWxA8crqvNxKz8yDSIT/GwrpzzBeQ20w tCtdIv1jczk6uNJe4rVoNxV0AwZjkv4MS5P8b0yU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Oliver O'Halloran , Sam Bobroff , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.14 031/127] powerpc/eeh: Only dump stack once if an MMIO loop is detected Date: Thu, 17 Sep 2020 22:10:44 -0400 Message-Id: <20200918021220.2066485-31-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918021220.2066485-1-sashal@kernel.org> References: <20200918021220.2066485-1-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: Oliver O'Halloran [ Upstream commit 4e0942c0302b5ad76b228b1a7b8c09f658a1d58a ] Many drivers don't check for errors when they get a 0xFFs response from an MMIO load. As a result after an EEH event occurs a driver can get stuck in a polling loop unless it some kind of internal timeout logic. Currently EEH tries to detect and report stuck drivers by dumping a stack trace after eeh_dev_check_failure() is called EEH_MAX_FAILS times on an already frozen PE. The value of EEH_MAX_FAILS was chosen so that a dump would occur every few seconds if the driver was spinning in a loop. This results in a lot of spurious stack traces in the kernel log. Fix this by limiting it to printing one stack trace for each PE freeze. If the driver is truely stuck the kernel's hung task detector is better suited to reporting the probelm anyway. Signed-off-by: Oliver O'Halloran Reviewed-by: Sam Bobroff Tested-by: Sam Bobroff Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191016012536.22588-1-oohall@gmail.com Signed-off-by: Sasha Levin --- arch/powerpc/kernel/eeh.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c index d2ba7936d0d33..7b46576962bfd 100644 --- a/arch/powerpc/kernel/eeh.c +++ b/arch/powerpc/kernel/eeh.c @@ -506,7 +506,7 @@ int eeh_dev_check_failure(struct eeh_dev *edev) rc = 1; if (pe->state & EEH_PE_ISOLATED) { pe->check_count++; - if (pe->check_count % EEH_MAX_FAILS == 0) { + if (pe->check_count == EEH_MAX_FAILS) { dn = pci_device_to_OF_node(dev); if (dn) location = of_get_property(dn, "ibm,loc-code", -- 2.25.1