From patchwork Tue Sep 29 10:59:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 263340 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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 AB22AC4727C for ; Tue, 29 Sep 2020 11:14:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5EC5821D46 for ; Tue, 29 Sep 2020 11:14:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378080; bh=IYgW8OLb/zFdIVzPPnLWfOpXT3c9vVAyrn9uipSSn7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=03uoebjk9CfEMIc8bJH8pczp4qeC6T2/9PcurwcOspeQ2t/WMYRHb3h+it3SJRyPG BpmiMerseD6UNGBmBz5ymJrYbpBe1PD2cx7ZFZ1S8P4i53TLZHYDKRmCcapjF8UyBE JrPTQSksq5xrO9NSSX6dxZthM9D5LdtxvOMdWMTQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729438AbgI2LOj (ORCPT ); Tue, 29 Sep 2020 07:14:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:57360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729434AbgI2LO0 (ORCPT ); Tue, 29 Sep 2020 07:14:26 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8E85C206A5; Tue, 29 Sep 2020 11:14:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378066; bh=IYgW8OLb/zFdIVzPPnLWfOpXT3c9vVAyrn9uipSSn7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PAasGaiqo2kbrt3DJeSAex2sh+4JPsH9diVXpTCMOL7oiSdM/xofSEKJtYmqeisUA CiKzT7kWzVSw2vaPTsKQMMB4oVfNohPwWlFKtHyDKaiCuT0ZvOgy2ErUwkrby1G0dS HhSru7TIAJHeHGYzu6KQRHDCXnx/z8zRdteBtM7Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver OHalloran , Sam Bobroff , Michael Ellerman , Sasha Levin Subject: [PATCH 4.14 049/166] powerpc/eeh: Only dump stack once if an MMIO loop is detected Date: Tue, 29 Sep 2020 12:59:21 +0200 Message-Id: <20200929105937.651479414@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105935.184737111@linuxfoundation.org> References: <20200929105935.184737111@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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",