From: Jay Vosburgh <jay.vosburgh@canonical.com> To: linux-pci@vger.kernel.org Cc: Bjorn Helgaas <bhelgaas@google.com>, Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Subject: [PATCH] PCI/ERR: Resolve regression in pcie_do_recovery Date: Wed, 29 Apr 2020 17:42:04 -0700 [thread overview] Message-ID: <12115.1588207324@famine> (raw) Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()"), introduced a regression, as pcie_do_recovery will discard the status result from report_frozen_detected. This can cause a failure to recover if _NEED_RESET is returned by report_frozen_detected and report_slot_reset is not invoked. Such an event can be induced for testing purposes by reducing the Max_Payload_Size of a PCIe bridge to less than that of a device downstream from the bridge, and then initating I/O through the device, resulting in oversize transactions. In the presence of DPC, this results in a containment event and attempted reset and recovery via pcie_do_recovery. After 6d2c89441571 report_slot_reset is not invoked, and the device does not recover. Inspection shows a similar path is plausible for a return of _CAN_RECOVER and the invocation of report_mmio_enabled. Resolve this by preserving the result of report_frozen_detected if reset_link does not return _DISCONNECT. Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com> --- drivers/pci/pcie/err.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c index 14bb8f54723e..e4274562f3a0 100644 --- a/drivers/pci/pcie/err.c +++ b/drivers/pci/pcie/err.c @@ -164,10 +164,17 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, pci_dbg(dev, "broadcast error_detected message\n"); if (state == pci_channel_io_frozen) { + pci_ers_result_t status2; + pci_walk_bus(bus, report_frozen_detected, &status); - status = reset_link(dev); - if (status != PCI_ERS_RESULT_RECOVERED) { + /* preserve status from report_frozen_detected to + * insure report_mmio_enabled or report_slot_reset are + * invoked even if reset_link returns _RECOVERED. + */ + status2 = reset_link(dev); + if (status2 != PCI_ERS_RESULT_RECOVERED) { pci_warn(dev, "link reset failed\n"); + status = status2; goto failed; } } else { -- 2.7.4
next reply other threads:[~2020-04-30 0:42 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-30 0:42 Jay Vosburgh [this message] 2020-04-30 1:15 ` Kuppuswamy, Sathyanarayanan 2020-04-30 19:35 ` Kuppuswamy, Sathyanarayanan 2020-04-30 20:41 ` Jay Vosburgh 2020-05-06 18:08 ` Jay Vosburgh 2020-05-09 6:35 ` Yicong Yang 2020-05-09 17:55 ` Kuppuswamy, Sathyanarayanan 2020-05-09 8:34 ` Yicong Yang [not found] <20200506203249.GA453633@bjorn-Precision-5520> 2020-05-07 0:56 ` Jay Vosburgh
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