From nobody Fri Dec 19 15:48:15 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A19F226888; Mon, 19 May 2025 21:37:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747690633; cv=none; b=rs083EwPVI0nLJD6RdtAcTrneaxpxjQwQtPbBpkdx2mptdGZu7os/V1gwPDAxYNVQn125c7pzGRUxwoeUnqC/KUatqBYnU1slGZYAjacqkuoBFeR2xT6g1K5RHo4Jz+hs9T0jdZNoP6LVx8RDQ1Mf04FJwEdL2kzR//RE+dYq8U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747690633; c=relaxed/simple; bh=pEzxMI1RPs1BcxgvGz2M9/A2tzz16x+dpGmkomDUbRE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fM4/yymgt0nFMdjDjXTiMC8wnOYPafSDRYpxX8KsGWWmdaAj8dtk67dyAiXY7TWtc4K5FWq2R4yQ+lHR0WijP1U6uE2Q5r3lLrHq4ig+N7xN6KQlyL4cbjz+FKjSTjqh6xTk82HoK0UqxNZR1DEdw4Ou1jNVZwBtLyQy6FCIwIE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lN3dFeon; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lN3dFeon" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8C0EC4CEE4; Mon, 19 May 2025 21:37:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747690632; bh=pEzxMI1RPs1BcxgvGz2M9/A2tzz16x+dpGmkomDUbRE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lN3dFeonzOxnEeK4/kIGrTtTf3uh5A8IISmo14XUj6cKz7P0lZQDC+HL1xgb3VhQe 9RQ167qx5Ein2TbOrW6x0Wf3OLPswgJBu9YL6e61EbWLlv6unNAWbUKV7SxJpm4VSt TYC9mePBKuh7kPFZq1jLidI/yh7+05FRbaBkoFzRr8+o4K4WSuaEqODL27zo6Y3YlH CflnR6LSgBEAJ4w8cFRRgNPMZAJ3PEGzu4KZQuVgCgA8QYnyptyOgTR4vE7JlYgvHq 1peTN5j0uw59iAnICPzDTWNStMcFcauHrKX225kFjXPmJxqVg1TXhTKA8cKtUCTbxu XziTIzsVbm25g== From: Bjorn Helgaas To: linux-pci@vger.kernel.org Cc: Jon Pan-Doh , Karolina Stolarek , Martin Petersen , Ben Fuller , Drew Walton , Anil Agrawal , Tony Luck , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Sathyanarayanan Kuppuswamy , Lukas Wunner , Jonathan Cameron , Sargun Dhillon , "Paul E . McKenney" , Mahesh J Salgaonkar , Oliver O'Halloran , Kai-Heng Feng , Keith Busch , Robert Richter , Terry Bowman , Shiju Jose , Dave Jiang , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Bjorn Helgaas Subject: [PATCH v6 14/16] PCI/AER: Introduce ratelimit for error logs Date: Mon, 19 May 2025 16:35:56 -0500 Message-ID: <20250519213603.1257897-15-helgaas@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250519213603.1257897-1-helgaas@kernel.org> References: <20250519213603.1257897-1-helgaas@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Jon Pan-Doh Spammy devices can flood kernel logs with AER errors and slow/stall execution. Add per-device ratelimits for AER correctable and uncorrectable errors that use the kernel defaults (10 per 5s). There are two AER logging entry points: - aer_print_error() is used by DPC and native AER - pci_print_aer() is used by GHES and CXL The native AER aer_print_error() case includes a loop that may log details from multiple devices. This is ratelimited by the union of ratelimits for these devices, set by add_error_device(), which collects the devices. If no such device is found, the Error Source message is ratelimited by the Root Port or RCEC that received the ERR_* message. The DPC aer_print_error() case is currently not ratelimited. The GHES and CXL pci_print_aer() cases are ratelimited by the Error Source device. Sargun at Meta reported internally that a flood of AER errors causes RCU CPU stall warnings and CSD-lock warnings. Tested using aer-inject[1]. Sent 11 AER errors. Observed 10 errors logged while AER stats (cat /sys/bus/pci/devices//aer_dev_correctable) show true count of 11. [1] https://git.kernel.org/pub/scm/linux/kernel/git/gong.chen/aer-inject.git [bhelgaas: commit log, factor out trace_aer_event() and aer_print_rp_info() changes to previous patches, collect single aer_err_info.ratelimit as union of ratelimits of all error source devices] Link: https://lore.kernel.org/r/20250321015806.954866-7-pandoh@google.com Reported-by: Sargun Dhillon Signed-off-by: Jon Pan-Doh Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.h | 3 ++- drivers/pci/pcie/aer.c | 49 ++++++++++++++++++++++++++++++++++++------ drivers/pci/pcie/dpc.c | 1 + 3 files changed, 46 insertions(+), 7 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 705f9ef58acc..65c466279ade 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -593,7 +593,8 @@ struct aer_err_info { unsigned int id:16; =20 unsigned int severity:2; /* 0:NONFATAL | 1:FATAL | 2:COR */ - unsigned int __pad1:5; + unsigned int ratelimit:1; /* 0=3Dskip, 1=3Dprint */ + unsigned int __pad1:4; unsigned int multi_error_valid:1; =20 unsigned int first_error:5; diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c index da62032bf024..c335e0bb9f51 100644 --- a/drivers/pci/pcie/aer.c +++ b/drivers/pci/pcie/aer.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -88,6 +89,10 @@ struct aer_report { u64 rootport_total_cor_errs; u64 rootport_total_fatal_errs; u64 rootport_total_nonfatal_errs; + + /* Ratelimits for errors */ + struct ratelimit_state cor_log_ratelimit; + struct ratelimit_state uncor_log_ratelimit; }; =20 #define AER_LOG_TLP_MASKS (PCI_ERR_UNC_POISON_TLP| \ @@ -379,6 +384,11 @@ void pci_aer_init(struct pci_dev *dev) =20 dev->aer_report =3D kzalloc(sizeof(*dev->aer_report), GFP_KERNEL); =20 + ratelimit_state_init(&dev->aer_report->cor_log_ratelimit, + DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); + ratelimit_state_init(&dev->aer_report->uncor_log_ratelimit, + DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); + /* * We save/restore PCI_ERR_UNCOR_MASK, PCI_ERR_UNCOR_SEVER, * PCI_ERR_COR_MASK, and PCI_ERR_CAP. Root and Root Complex Event @@ -672,6 +682,18 @@ static void pci_rootport_aer_stats_incr(struct pci_dev= *pdev, } } =20 +static int aer_ratelimit(struct pci_dev *dev, unsigned int severity) +{ + struct ratelimit_state *ratelimit; + + if (severity =3D=3D AER_CORRECTABLE) + ratelimit =3D &dev->aer_report->cor_log_ratelimit; + else + ratelimit =3D &dev->aer_report->uncor_log_ratelimit; + + return __ratelimit(ratelimit); +} + static void __aer_print_error(struct pci_dev *dev, struct aer_err_info *in= fo) { const char **strings; @@ -715,6 +737,9 @@ void aer_print_error(struct pci_dev *dev, struct aer_er= r_info *info) =20 pci_dev_aer_stats_incr(dev, info); =20 + if (!info->ratelimit) + return; + if (!info->status) { pci_err(dev, "PCIe Bus Error: severity=3D%s, type=3DInaccessible, (Unreg= istered Agent ID)\n", aer_error_severity_string[info->severity]); @@ -785,6 +810,9 @@ void pci_print_aer(struct pci_dev *dev, int aer_severit= y, =20 pci_dev_aer_stats_incr(dev, &info); =20 + if (!aer_ratelimit(dev, info.severity)) + return; + layer =3D AER_GET_LAYER_ERROR(aer_severity, status); agent =3D AER_GET_AGENT(aer_severity, status); =20 @@ -815,8 +843,14 @@ EXPORT_SYMBOL_NS_GPL(pci_print_aer, "CXL"); */ static int add_error_device(struct aer_err_info *e_info, struct pci_dev *d= ev) { + /* + * Ratelimit AER log messages. Generally we add the Error Source + * device, but there are is_error_source() cases that can result in + * multiple devices being added here, so we OR them all together. + */ if (e_info->error_dev_num < AER_MAX_MULTI_ERR_DEVICES) { e_info->dev[e_info->error_dev_num] =3D pci_dev_get(dev); + e_info->ratelimit |=3D aer_ratelimit(dev, e_info->severity); e_info->error_dev_num++; return 0; } @@ -914,7 +948,7 @@ static int find_device_iter(struct pci_dev *dev, void *= data) * e_info->error_dev_num and e_info->dev[], based on the given information. */ static bool find_source_device(struct pci_dev *parent, - struct aer_err_info *e_info) + struct aer_err_info *e_info) { struct pci_dev *dev =3D parent; int result; @@ -935,10 +969,12 @@ static bool find_source_device(struct pci_dev *parent, /* * If we didn't find any devices with errors logged in the AER * Capability, just print the Error Source ID from the Root Port or - * RCEC that received an ERR_* Message. + * RCEC that received an ERR_* Message, ratelimited by the RP or + * RCEC. */ if (!e_info->error_dev_num) { - aer_print_source(parent, e_info, " (no details found)"); + if (aer_ratelimit(parent, e_info->severity)) + aer_print_source(parent, e_info, " (no details found)"); return false; } return true; @@ -1147,9 +1183,10 @@ static void aer_recover_work_func(struct work_struct= *work) pdev =3D pci_get_domain_bus_and_slot(entry.domain, entry.bus, entry.devfn); if (!pdev) { - pr_err("no pci_dev for %04x:%02x:%02x.%x\n", - entry.domain, entry.bus, - PCI_SLOT(entry.devfn), PCI_FUNC(entry.devfn)); + pr_err_ratelimited("%04x:%02x:%02x.%x: no pci_dev found\n", + entry.domain, entry.bus, + PCI_SLOT(entry.devfn), + PCI_FUNC(entry.devfn)); continue; } pci_print_aer(pdev, entry.severity, entry.regs); diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c index 34af0ea45c0d..597df7790f36 100644 --- a/drivers/pci/pcie/dpc.c +++ b/drivers/pci/pcie/dpc.c @@ -301,6 +301,7 @@ void dpc_process_error(struct pci_dev *pdev) else if (reason =3D=3D PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR && dpc_get_aer_uncorrect_severity(pdev, &info) && aer_get_device_error_info(pdev, &info)) { + info.ratelimit =3D 1; /* no ratelimiting */ aer_print_error(pdev, &info); pci_aer_clear_nonfatal_status(pdev); pci_aer_clear_fatal_status(pdev); --=20 2.43.0