From patchwork Sun Sep 27 03:28:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11801745 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ACB44618 for ; Sun, 27 Sep 2020 03:30:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DFC92100A for ; Sun, 27 Sep 2020 03:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730096AbgI0DaE (ORCPT ); Sat, 26 Sep 2020 23:30:04 -0400 Received: from mga12.intel.com ([192.55.52.136]:65381 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726478AbgI0DaD (ORCPT ); Sat, 26 Sep 2020 23:30:03 -0400 IronPort-SDR: otU/DOko7/UUM1bF24BLFiBdDSrvH0sjVWhbaFUUv5Hez4vIl/cLSfriPKut72UYDAwJCX/McF cA1vcIvysgYQ== X-IronPort-AV: E=McAfee;i="6000,8403,9756"; a="141242659" X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="141242659" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2020 20:30:03 -0700 IronPort-SDR: ESeO+6bAJMd0p7YOx10yvqkJqq8JQmTsah36nE2wb8DBROGCUbPwkI3/Hz5UrqveafuUCktXL5 YsXqC+D94XsQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="337697494" Received: from shskylake.sh.intel.com ([10.239.48.137]) by fmsmga004.fm.intel.com with ESMTP; 26 Sep 2020 20:30:00 -0700 From: Ethan Zhao To: bhelgaas@google.com, oohall@gmail.com, ruscur@russell.cc, lukas@wunner.de, andriy.shevchenko@linux.intel.com, stuart.w.hayes@gmail.com, mr.nuke.me@gmail.com, mika.westerberg@linux.intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, pei.p.jia@intel.com, ashok.raj@linux.intel.com, sathyanarayanan.kuppuswamy@intel.com, Ethan Zhao Subject: [PATCH 1/5 V2] PCI: define a function to check and wait till port finish DPC handling Date: Sat, 26 Sep 2020 23:28:25 -0400 Message-Id: <20200927032829.11321-2-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200927032829.11321-1-haifeng.zhao@intel.com> References: <20200927032829.11321-1-haifeng.zhao@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Once root port DPC capability is enabled and triggered, at the beginning of DPC is triggered, the DPC status bits are set by hardware and then sends DPC/DLLSC/PDC interrupts to OS DPC and pciehp drivers, it will take the port and software DPC interrupt handler 10ms to 50ms (test data on ICS(Ice Lake SP platform, see https://en.wikichip.org/wiki/intel/microarchitectures/ice_lake_(server) & stable 5.9-rc6) to complete the DPC containment procedure till the DPC status is cleared at the end of the DPC interrupt handler. We use this function to check if the root port is in DPC handling status and wait till the hardware and software completed the procedure. Signed-off-by: Ethan Zhao Tested-by: Wen Jin Tested-by: Shanshan Zhang Reviewed-by: Andy Shevchenko --- changes: V2：align ICS code name to public doc. include/linux/pci.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/include/linux/pci.h b/include/linux/pci.h index 835530605c0d..5beb76c6ae26 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -38,6 +38,7 @@ #include #include #include +#include #include #include @@ -2427,4 +2428,34 @@ void pci_uevent_ers(struct pci_dev *pdev, enum pci_ers_result err_type); WARN_ONCE(condition, "%s %s: " fmt, \ dev_driver_string(&(pdev)->dev), pci_name(pdev), ##arg) +#ifdef CONFIG_PCIE_DPC +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev) +{ + u16 cap = pdev->dpc_cap, status; + u16 loop = 0; + + if (!cap) { + pci_WARN_ONCE(pdev, !cap, "No DPC capability initiated\n"); + return false; + } + pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status); + pci_dbg(pdev, "DPC status %x, cap %x\n", status, cap); + while (status & PCI_EXP_DPC_STATUS_TRIGGER && loop < 100) { + msleep(10); + loop++; + pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status); + } + if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) { + pci_dbg(pdev, "Out of DPC %x, cost %d ms\n", status, loop*10); + return true; + } + pci_dbg(pdev, "Timeout to wait port out of DPC status\n"); + return false; +} +#else +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev) +{ + return true; +} +#endif #endif /* LINUX_PCI_H */ From patchwork Sun Sep 27 03:28:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11801769 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD73A139F for ; Sun, 27 Sep 2020 05:03:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8054239D4 for ; Sun, 27 Sep 2020 05:03:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726840AbgI0FDS (ORCPT ); Sun, 27 Sep 2020 01:03:18 -0400 Received: from mga12.intel.com ([192.55.52.136]:47387 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726478AbgI0FDS (ORCPT ); Sun, 27 Sep 2020 01:03:18 -0400 IronPort-SDR: V6oZxEI7I9+/mf1be2itzDQOX1SFx4jDaxcuc4crQ3u3TVA5BzLxwMpkdir0HypgFpAB63emXx 3NfnA9o0EM6w== X-IronPort-AV: E=McAfee;i="6000,8403,9756"; a="141242666" X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="141242666" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2020 20:30:06 -0700 IronPort-SDR: U+gJ2Y6Ro6FxAxEr9crR2KOAeN6f4/ZbMsD5uJTYrht0h83sIUfa13XSyw/S6PUz6hJNPDdOaB KDLwr5vlJucg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="337697520" Received: from shskylake.sh.intel.com ([10.239.48.137]) by fmsmga004.fm.intel.com with ESMTP; 26 Sep 2020 20:30:03 -0700 From: Ethan Zhao To: bhelgaas@google.com, oohall@gmail.com, ruscur@russell.cc, lukas@wunner.de, andriy.shevchenko@linux.intel.com, stuart.w.hayes@gmail.com, mr.nuke.me@gmail.com, mika.westerberg@linux.intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, pei.p.jia@intel.com, ashok.raj@linux.intel.com, sathyanarayanan.kuppuswamy@intel.com, Ethan Zhao Subject: [PATCH 2/5 V2] PCI: pciehp: check and wait port status out of DPC before handling DLLSC and PDC Date: Sat, 26 Sep 2020 23:28:26 -0400 Message-Id: <20200927032829.11321-3-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200927032829.11321-1-haifeng.zhao@intel.com> References: <20200927032829.11321-1-haifeng.zhao@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When root port has DPC capability and it is enabled, then triggered by errors, DPC DLLSC and PDC interrupts will be sent to DPC driver, pciehp driver at the same time. That will cause following result: 1. Link and device are recovered by hardware DPC and software DPC driver, device isn't removed, but the pciehp might treat it as device was hot removed. 2. Race condition happens bettween pciehp_unconfigure_device() called by pciehp_ist() in pciehp driver and pci_do_recovery() called by dpc_handler in DPC driver. no luck, there is no lock to protect pci_stop_and_remove_bus_device() against pci_walk_bus(), they hold different samphore and mutex, pci_stop_and_remove_bus_device holds pci_rescan_remove_lock, and pci_walk_bus() holds pci_bus_sem. This race condition is not purely code analysis, it could be triggered by following command series: # setpci -s 64:02.0 0x196.w=000a // 64:02.0 rootport has DPC capability # setpci -s 65:00.0 0x04.w=0544 // 65:00.0 NVMe SSD populated in port # mount /dev/nvme0n1p1 nvme One shot will cause system panic and NULL pointer reference happened. (tested on stable 5.8 & ICS(Ice Lake SP platform, see https://en.wikichip.org/wiki/intel/microarchitectures/ice_lake_(server)) Buffer I/O error on dev nvme0n1p1, logical block 3328, async page read BUG: kernel NULL pointer dereference, address: 0000000000000050 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 Oops: 0000 [#1] SMP NOPTI CPU: 12 PID: 513 Comm: irq/124-pcie-dp Not tainted 5.8.0 el8.x86_64+ #1 RIP: 0010:report_error_detected.cold.4+0x7d/0xe6 Code: b6 d0 e8 e8 fe 11 00 e8 16 c5 fb ff be 06 00 00 00 48 89 df e8 d3 65 ff ff b8 06 00 00 00 e9 75 fc ff ff 48 8b 43 68 45 31 c9 <48> 8b 50 50 48 83 3a 00 41 0f 94 c1 45 31 c0 48 85 d2 41 0f 94 c0 RSP: 0018:ff8e06cf8762fda8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ff4e3eaacf42a000 RCX: ff4e3eb31f223c01 RDX: ff4e3eaacf42a140 RSI: ff4e3eb31f223c00 RDI: ff4e3eaacf42a138 RBP: ff8e06cf8762fdd0 R08: 00000000000000bf R09: 0000000000000000 R10: 000000eb8ebeab53 R11: ffffffff93453258 R12: 0000000000000002 R13: ff4e3eaacf42a130 R14: ff8e06cf8762fe2c R15: ff4e3eab44733828 FS: 0000000000000000(0000) GS:ff4e3eab1fd00000(0000) knl GS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000050 CR3: 0000000f8f80a004 CR4: 0000000000761ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? report_normal_detected+0x20/0x20 report_frozen_detected+0x16/0x20 pci_walk_bus+0x75/0x90 ? dpc_irq+0x90/0x90 pcie_do_recovery+0x157/0x201 ? irq_finalize_oneshot.part.47+0xe0/0xe0 dpc_handler+0x29/0x40 irq_thread_fn+0x24/0x60 irq_thread+0xea/0x170 ? irq_forced_thread_fn+0x80/0x80 ? irq_thread_check_affinity+0xf0/0xf0 kthread+0x124/0x140 ? kthread_park+0x90/0x90 ret_from_fork+0x1f/0x30 Modules linked in: nft_fib_inet......... CR2: 0000000000000050 With this patch, the handling flow of DPC containment and hotplug is partly ordered and serialized, let hardware DPC do the controller reset etc recovery action first, then DPC driver handling the call-back from device drivers, clear the DPC status, at the end, pciehp handle the DLLSC and PDC etc. Signed-off-by: Ethan Zhao Tested-by: Wen Jin Tested-by: Shanshan Zhang Reviewed-by: Andy Shevchenko --- Changes: V2: revise doc according to Andy's suggestion. drivers/pci/hotplug/pciehp_hpc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 53433b37e181..6f271160f18d 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -710,8 +710,10 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id) down_read(&ctrl->reset_lock); if (events & DISABLE_SLOT) pciehp_handle_disable_request(ctrl); - else if (events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC)) + else if (events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC)) { + pci_wait_port_outdpc(pdev); pciehp_handle_presence_or_link_change(ctrl, events); + } up_read(&ctrl->reset_lock); ret = IRQ_HANDLED; From patchwork Sun Sep 27 03:28:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11801763 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B4DBF618 for ; Sun, 27 Sep 2020 03:43:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9930421D95 for ; Sun, 27 Sep 2020 03:43:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729580AbgI0DnO (ORCPT ); Sat, 26 Sep 2020 23:43:14 -0400 Received: from mga12.intel.com ([192.55.52.136]:58924 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729125AbgI0DnN (ORCPT ); Sat, 26 Sep 2020 23:43:13 -0400 IronPort-SDR: 23b77/7KnAKEb7ZNGM+E/10kvKchstZXKryJx7pA3PbegISwZdHcVTQADATbx58qS02aA11quB gTykfBHOAxsw== X-IronPort-AV: E=McAfee;i="6000,8403,9756"; a="141242669" X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="141242669" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2020 20:30:09 -0700 IronPort-SDR: /wwLhQ00ZDWYLeunlYjmlNNi7cd4uT8kCVVDO92RCiFu8Bwobqd+oPQSWp41oA57CvFTMyzLfR fyxzLJlly+3w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="337697529" Received: from shskylake.sh.intel.com ([10.239.48.137]) by fmsmga004.fm.intel.com with ESMTP; 26 Sep 2020 20:30:06 -0700 From: Ethan Zhao To: bhelgaas@google.com, oohall@gmail.com, ruscur@russell.cc, lukas@wunner.de, andriy.shevchenko@linux.intel.com, stuart.w.hayes@gmail.com, mr.nuke.me@gmail.com, mika.westerberg@linux.intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, pei.p.jia@intel.com, ashok.raj@linux.intel.com, sathyanarayanan.kuppuswamy@intel.com, Ethan Zhao Subject: [PATCH 3/5 V2] PCI/ERR: get device before call device driver to avoid NULL pointer reference Date: Sat, 26 Sep 2020 23:28:27 -0400 Message-Id: <20200927032829.11321-4-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200927032829.11321-1-haifeng.zhao@intel.com> References: <20200927032829.11321-1-haifeng.zhao@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org During DPC error injection test we found there is race condition between pciehp and DPC driver, NULL pointer reference caused panic as following # setpci -s 64:02.0 0x196.w=000a // 64:02.0 is rootport has DPC capability # setpci -s 65:00.0 0x04.w=0544 // 65:00.0 is NVMe SSD populated in above port # mount /dev/nvme0n1p1 nvme (tested on stable 5.8 & ICS(Ice Lake SP platform, see https://en.wikichip.org/wiki/intel/microarchitectures/ice_lake_(server)) Buffer I/O error on dev nvme0n1p1, logical block 468843328, async page read BUG: kernel NULL pointer dereference, address: 0000000000000050 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 Oops: 0000 [#1] SMP NOPTI CPU: 12 PID: 513 Comm: irq/124-pcie-dp Not tainted 5.8.0-0.0.7.el8.x86_64+ #1 RIP: 0010:report_error_detected.cold.4+0x7d/0xe6 Code: b6 d0 e8 e8 fe 11 00 e8 16 c5 fb ff be 06 00 00 00 48 89 df e8 d3 65 ff ff b8 06 00 00 00 e9 75 fc ff ff 48 8b 43 68 45 31 c9 <48> 8b 50 50 48 83 3a 00 41 0f 94 c1 45 31 c0 48 85 d2 41 0f 94 c0 RSP: 0018:ff8e06cf8762fda8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ff4e3eaacf42a000 RCX: ff4e3eb31f223c01 RDX: ff4e3eaacf42a140 RSI: ff4e3eb31f223c00 RDI: ff4e3eaacf42a138 RBP: ff8e06cf8762fdd0 R08: 00000000000000bf R09: 0000000000000000 R10: 000000eb8ebeab53 R11: ffffffff93453258 R12: 0000000000000002 R13: ff4e3eaacf42a130 R14: ff8e06cf8762fe2c R15: ff4e3eab44733828 FS: 0000000000000000(0000) GS:ff4e3eab1fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000050 CR3: 0000000f8f80a004 CR4: 0000000000761ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? report_normal_detected+0x20/0x20 report_frozen_detected+0x16/0x20 pci_walk_bus+0x75/0x90 ? dpc_irq+0x90/0x90 pcie_do_recovery+0x157/0x201 ? irq_finalize_oneshot.part.47+0xe0/0xe0 dpc_handler+0x29/0x40 irq_thread_fn+0x24/0x60 irq_thread+0xea/0x170 ? irq_forced_thread_fn+0x80/0x80 ? irq_thread_check_affinity+0xf0/0xf0 kthread+0x124/0x140 ? kthread_park+0x90/0x90 ret_from_fork+0x1f/0x30 Modules linked in: nft_fib_inet......... CR2: 0000000000000050 Though we partly close the race condition with patch 'PCI: pciehp: check and wait port status out of DPC before handling DLLSC and PDC', but there is no hardware spec or software sequence to guarantee the pcie_ist() run into pci_wait_port_outdpc() first or DPC triggered status bits being set first when errors triggered DPC containment procedure, so device still could be removed by function pci_stop_and_removed_bus_device() then freed by pci_dev_put() in pciehp driver first during pcie_do_recover()/ pci_walk_bus() is called by dpc_handler() in DPC driver. Maybe unify pci_bus_sem and pci_rescan_remove_lock to serialize the removal and walking operation is the right way, but here we use pci_dev_get() to increase the reference count of device before using the device to avoid it is freed in use. With this patch and patch 'PCI: pciehp: check and wait port status out of DPC before handling DLLSC and PDC', stable 5.9-rc6 could pass the error injection test and no panic happened. Brute DPC error injection script: for i in {0..100} do setpci -s 64:02.0 0x196.w=000a setpci -s 65:00.0 0x04.w=0544 mount /dev/nvme0n1p1 /root/nvme sleep 1 done Signed-off-by: Ethan Zhao Tested-by: Wen Jin Tested-by: Shanshan Zhang Reviewed-by: Andy Shevchenko --- Changes: V2: revise doc according to Andy's suggestion. drivers/pci/pcie/err.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c index c543f419d8f9..e35c4480c86b 100644 --- a/drivers/pci/pcie/err.c +++ b/drivers/pci/pcie/err.c @@ -52,6 +52,8 @@ static int report_error_detected(struct pci_dev *dev, pci_ers_result_t vote; const struct pci_error_handlers *err_handler; + if (!pci_dev_get(dev)) + return 0; device_lock(&dev->dev); if (!pci_dev_set_io_state(dev, state) || !dev->driver || @@ -76,6 +78,7 @@ static int report_error_detected(struct pci_dev *dev, pci_uevent_ers(dev, vote); *result = merge_result(*result, vote); device_unlock(&dev->dev); + pci_dev_put(dev); return 0; } @@ -94,6 +97,8 @@ static int report_mmio_enabled(struct pci_dev *dev, void *data) pci_ers_result_t vote, *result = data; const struct pci_error_handlers *err_handler; + if (!pci_dev_get(dev)) + return 0; device_lock(&dev->dev); if (!dev->driver || !dev->driver->err_handler || @@ -105,6 +110,7 @@ static int report_mmio_enabled(struct pci_dev *dev, void *data) *result = merge_result(*result, vote); out: device_unlock(&dev->dev); + pci_dev_put(dev); return 0; } @@ -113,6 +119,8 @@ static int report_slot_reset(struct pci_dev *dev, void *data) pci_ers_result_t vote, *result = data; const struct pci_error_handlers *err_handler; + if (!pci_dev_get(dev)) + return 0; device_lock(&dev->dev); if (!dev->driver || !dev->driver->err_handler || @@ -124,6 +132,7 @@ static int report_slot_reset(struct pci_dev *dev, void *data) *result = merge_result(*result, vote); out: device_unlock(&dev->dev); + pci_dev_put(dev); return 0; } @@ -131,6 +140,8 @@ static int report_resume(struct pci_dev *dev, void *data) { const struct pci_error_handlers *err_handler; + if (!pci_dev_get(dev)) + return 0; device_lock(&dev->dev); if (!pci_dev_set_io_state(dev, pci_channel_io_normal) || !dev->driver || @@ -143,6 +154,7 @@ static int report_resume(struct pci_dev *dev, void *data) out: pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED); device_unlock(&dev->dev); + pci_dev_put(dev); return 0; } From patchwork Sun Sep 27 03:28:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11801747 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C83306CA for ; Sun, 27 Sep 2020 03:30:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA27C2100A for ; Sun, 27 Sep 2020 03:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730251AbgI0DaN (ORCPT ); Sat, 26 Sep 2020 23:30:13 -0400 Received: from mga12.intel.com ([192.55.52.136]:65386 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730250AbgI0DaN (ORCPT ); Sat, 26 Sep 2020 23:30:13 -0400 IronPort-SDR: NxTuNn9+vb+x2PaDySmV0JOT6jJbvwlVXQwCIZ+WjPmm4qi24g3gT6PxcNqwH3mdMK8qgqLIf7 l9UM12bnhMXA== X-IronPort-AV: E=McAfee;i="6000,8403,9756"; a="141242670" X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="141242670" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2020 20:30:12 -0700 IronPort-SDR: k7kuHZOWuM6IQrSnGRUR3zYbRDGCMufzqKZhok+pDtbmKePH/qNPUOJY5HucATi1ycN9zgk3KE 870H3MnH+aJw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="337697538" Received: from shskylake.sh.intel.com ([10.239.48.137]) by fmsmga004.fm.intel.com with ESMTP; 26 Sep 2020 20:30:09 -0700 From: Ethan Zhao To: bhelgaas@google.com, oohall@gmail.com, ruscur@russell.cc, lukas@wunner.de, andriy.shevchenko@linux.intel.com, stuart.w.hayes@gmail.com, mr.nuke.me@gmail.com, mika.westerberg@linux.intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, pei.p.jia@intel.com, ashok.raj@linux.intel.com, sathyanarayanan.kuppuswamy@intel.com, Ethan Zhao Subject: [PATCH 4/5 V2] PCI: only return true when dev io state is really changed Date: Sat, 26 Sep 2020 23:28:28 -0400 Message-Id: <20200927032829.11321-5-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200927032829.11321-1-haifeng.zhao@intel.com> References: <20200927032829.11321-1-haifeng.zhao@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When uncorrectable error happens, AER driver and DPC driver interrupt handlers likely call pcie_do_recovery() ->pci_walk_bus() ->report_frozen_detected() with pci_channel_io_frozen the same time. If pci_dev_set_io_state() return true even if the original state is pci_channel_io_frozen, that will cause AER or DPC handler re-enter the error detecting and recovery procedure one after another. The result is the recovery flow mixed between AER and DPC. So simplify the pci_dev_set_io_state() function to only return true when dev->error_state is changed. Signed-off-by: Ethan Zhao Tested-by: Wen Jin Tested-by: Shanshan Zhang Reviewed-by: Andy Shevchenko Reviewed-by: Alexandru Gagniuc --- Changes: V2: revise doc and code flow according to Andy's suggestion. drivers/pci/pci.h | 34 +++++----------------------------- 1 file changed, 5 insertions(+), 29 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index fa12f7cbc1a0..387f891ce6a1 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -362,35 +362,11 @@ static inline bool pci_dev_set_io_state(struct pci_dev *dev, bool changed = false; device_lock_assert(&dev->dev); - switch (new) { - case pci_channel_io_perm_failure: - switch (dev->error_state) { - case pci_channel_io_frozen: - case pci_channel_io_normal: - case pci_channel_io_perm_failure: - changed = true; - break; - } - break; - case pci_channel_io_frozen: - switch (dev->error_state) { - case pci_channel_io_frozen: - case pci_channel_io_normal: - changed = true; - break; - } - break; - case pci_channel_io_normal: - switch (dev->error_state) { - case pci_channel_io_frozen: - case pci_channel_io_normal: - changed = true; - break; - } - break; - } - if (changed) - dev->error_state = new; + if (dev->error_state == new) + return changed; + + dev->error_state = new; + changed = true; return changed; } From patchwork Sun Sep 27 03:28:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11801749 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E6CE01746 for ; Sun, 27 Sep 2020 03:30:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D83542100A for ; Sun, 27 Sep 2020 03:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730263AbgI0DaQ (ORCPT ); Sat, 26 Sep 2020 23:30:16 -0400 Received: from mga12.intel.com ([192.55.52.136]:65386 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730250AbgI0DaQ (ORCPT ); Sat, 26 Sep 2020 23:30:16 -0400 IronPort-SDR: H34r4B0OK17luwr0NjGtK/I5dtFit4OYxetEP7TYt8Cfe1qmLgZfobCxTKzGZ7iRX4hfaKKeqL RRSAOKGCmqCA== X-IronPort-AV: E=McAfee;i="6000,8403,9756"; a="141242672" X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="141242672" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2020 20:30:16 -0700 IronPort-SDR: Q7mHcK+KZFD3rtG0Zw1IMqVNWMwH3L84/t8EZ7k7K823g71MfyifCe9X/UQuPMTIc3FUjH06VM mO9Khs58ThoQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="337697550" Received: from shskylake.sh.intel.com ([10.239.48.137]) by fmsmga004.fm.intel.com with ESMTP; 26 Sep 2020 20:30:13 -0700 From: Ethan Zhao To: bhelgaas@google.com, oohall@gmail.com, ruscur@russell.cc, lukas@wunner.de, andriy.shevchenko@linux.intel.com, stuart.w.hayes@gmail.com, mr.nuke.me@gmail.com, mika.westerberg@linux.intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, pei.p.jia@intel.com, ashok.raj@linux.intel.com, sathyanarayanan.kuppuswamy@intel.com, Ethan Zhao Subject: [PATCH 5/5 V2] PCI/ERR: don't mix io state not changed and no driver together Date: Sat, 26 Sep 2020 23:28:29 -0400 Message-Id: <20200927032829.11321-6-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200927032829.11321-1-haifeng.zhao@intel.com> References: <20200927032829.11321-1-haifeng.zhao@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When we see 'can't recover (no error_detected callback)' on console, Maybe the reason is io state is not changed by calling pci_dev_set_io_state(), that is confused. fix it. Signed-off-by: Ethan Zhao Tested-by: Wen Jin Tested-by: Shanshan Zhang --- Chagnes: V2: no change. drivers/pci/pcie/err.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c index e35c4480c86b..d85f27c90c26 100644 --- a/drivers/pci/pcie/err.c +++ b/drivers/pci/pcie/err.c @@ -55,8 +55,10 @@ static int report_error_detected(struct pci_dev *dev, if (!pci_dev_get(dev)) return 0; device_lock(&dev->dev); - if (!pci_dev_set_io_state(dev, state) || - !dev->driver || + if (!pci_dev_set_io_state(dev, state)) { + pci_dbg(dev, "Device might already being in error handling ...\n"); + vote = PCI_ERS_RESULT_NONE; + } else if (!dev->driver || !dev->driver->err_handler || !dev->driver->err_handler->error_detected) { /*