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 CC679C433F5 for ; Wed, 11 May 2022 23:28:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349308AbiEKX2C (ORCPT ); Wed, 11 May 2022 19:28:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245183AbiEKX2B (ORCPT ); Wed, 11 May 2022 19:28:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C67BE694AB; Wed, 11 May 2022 16:28:00 -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 6120261DC9; Wed, 11 May 2022 23:28:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 751F9C340EE; Wed, 11 May 2022 23:27:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652311679; bh=siF8PIsP3XHsVSZH5Wv97Tl+fZ+3A6Kd5SrYh1Feyp8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=cmdoL7mS/UXMhq4bFqDfAewpfd7ifK2Y83cZJgqQAb5UvtYPro4j5Lf4DTm09oqMH 5Tivg2wc2r6fMg7SSjY5/eHYp/DhPkwbtcFBoM9OPWI5jS4wRAgjt0n5CduKdlIsml RgCP7NLJCJZlQ4o5Yc9/2tpjejnHsv3jTRn2sG6sFm78MGBncAjhNFoHSha+Lr4qlR 6FJ4c0OsGA9yowCGZzj9mKDLvuuK52Vx00IdduEhyFi+DgzqNY6FYEQMIZZVszJy2r c6h5iC2Zn9OB2DofxQiphWhzyBJSO4J6QFe8OY55YeLeK71aMUSIDEByxgHMOoCdj/ jNDlLzEdn3/bQ== Date: Wed, 11 May 2022 18:27:57 -0500 From: Bjorn Helgaas To: Kuppuswamy Sathyanarayanan Cc: Bjorn Helgaas , Russell Currey , Oliver OHalloran , linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] PCI/AER: Handle Multi UnCorrectable/Correctable errors properly Message-ID: <20220511232757.GA829078@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220418150237.1021519-1-sathyanarayanan.kuppuswamy@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Apr 18, 2022 at 03:02:37PM +0000, Kuppuswamy Sathyanarayanan wrote: > Currently the aer_irq() handler returns IRQ_NONE for cases without bits > PCI_ERR_ROOT_UNCOR_RCV or PCI_ERR_ROOT_COR_RCV are set. But this > assumption is incorrect. > > Consider a scenario where aer_irq() is triggered for a correctable > error, and while we process the error and before we clear the error > status in "Root Error Status" register, if the same kind of error > is triggered again, since aer_irq() only clears events it saw, the > multi-bit error is left in tact. This will cause the interrupt to fire > again, resulting in entering aer_irq() with just the multi-bit error > logged in the "Root Error Status" register. > > Repeated AER recovery test has revealed this condition does happen > and this prevents any new interrupt from being triggered. Allow to > process interrupt even if only multi-correctable (BIT 1) or > multi-uncorrectable bit (BIT 3) is set. > > Also note that, for cases with only multi-bit error is set, since this > is not the first occurrence of the error, PCI_ERR_ROOT_ERR_SRC may have > zero or some junk value. So we cannot cleanly process this error > information using aer_isr_one_error(). All we are attempting with this > fix is to make sure error interrupt processing can continue in this > scenario. > > This error can be reproduced by making following changes to the > aer_irq() function and by executing the given test commands. > > static irqreturn_t aer_irq(int irq, void *context) > struct aer_err_source e_src = {}; > > pci_read_config_dword(rp, aer + PCI_ERR_ROOT_STATUS, > &e_src.status); > + pci_dbg(pdev->port, "Root Error Status: %04x\n", > + e_src.status); > if (!(e_src.status & AER_ERR_STATUS_MASK)) > return IRQ_NONE; > > + mdelay(5000); > > # Prep injection data for a correctable error. > $ cd /sys/kernel/debug/apei/einj > $ echo 0x00000040 > error_type > $ echo 0x4 > flags > $ echo 0x891000 > param4 > > # Root Error Status is initially clear > $ setpci -s ECAP0001+0x30.w > 0000 > > # Inject one error > $ echo 1 > error_inject > > # Interrupt received > pcieport : AER: Root Error Status 0001 > > # Inject another error (within 5 seconds) > $ echo 1 > error_inject > > # You will get a new IRQ with only multiple ERR_COR bit set > pcieport : AER: Root Error Status 0002 > > Currently, the above issue has been only reproduced in the ICL server > platform. > > [Eric: proposed reproducing steps] > Fixes: 4696b828ca37 ("PCI/AER: Hoist aerdrv.c, aer_inject.c up to drivers/pci/pcie/") 4696b828ca37 only *moves* drivers/pci/pcie/aer/aerdrv.c to drivers/pci/pcie/aer.c, so I don't think it's related. I think the actual change of interest is e167bfcaa4cd ("PCI: aerdrv: remove magical ROOT_ERR_STATUS_MASKS") [1]. It looks like we did exactly what you propose before that commit. I can update this unless you disagree. [1] https://git.kernel.org/linus/e167bfcaa4cd > Reported-by: Eric Badger > Reviewed-by: Ashok Raj > Signed-off-by: Kuppuswamy Sathyanarayanan > --- > > Changes since v2: > * Added more details to the commit log. > * Rebased on v5.18-rc1. > > Changes since v1: > * Added Fixes tag. > * Included reproducing steps proposed by Eric. > > drivers/pci/pcie/aer.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > index 9fa1f97e5b27..7952e5efd6cf 100644 > --- a/drivers/pci/pcie/aer.c > +++ b/drivers/pci/pcie/aer.c > @@ -101,6 +101,11 @@ struct aer_stats { > #define ERR_COR_ID(d) (d & 0xffff) > #define ERR_UNCOR_ID(d) (d >> 16) > > +#define AER_ERR_STATUS_MASK (PCI_ERR_ROOT_UNCOR_RCV | \ > + PCI_ERR_ROOT_COR_RCV | \ > + PCI_ERR_ROOT_MULTI_COR_RCV | \ > + PCI_ERR_ROOT_MULTI_UNCOR_RCV) > + > static int pcie_aer_disable; > static pci_ers_result_t aer_root_reset(struct pci_dev *dev); > > @@ -1196,7 +1201,7 @@ static irqreturn_t aer_irq(int irq, void *context) > struct aer_err_source e_src = {}; > > pci_read_config_dword(rp, aer + PCI_ERR_ROOT_STATUS, &e_src.status); > - if (!(e_src.status & (PCI_ERR_ROOT_UNCOR_RCV|PCI_ERR_ROOT_COR_RCV))) > + if (!(e_src.status & AER_ERR_STATUS_MASK)) > return IRQ_NONE; > > pci_read_config_dword(rp, aer + PCI_ERR_ROOT_ERR_SRC, &e_src.id); > -- > 2.25.1 >