From: Bjorn Helgaas <helgaas@kernel.org>
To: Zhuo Chen <chenzhuo.1@bytedance.com>
Cc: sathyanarayanan.kuppuswamy@linux.intel.com, bhelgaas@google.com,
ruscur@russell.cc, oohall@gmail.com, fancer.lancer@gmail.com,
jdmason@kudzu.us, dave.jiang@intel.com, allenbh@gmail.com,
james.smart@broadcom.com, dick.kennedy@broadcom.com,
jejb@linux.ibm.com, martin.petersen@oracle.com,
linuxppc-dev@lists.ozlabs.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, ntb@lists.linux.dev,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH v3 8/9] PCI/ERR: Clear fatal error status when pci_channel_io_frozen
Date: Tue, 6 Dec 2022 15:42:07 -0600 [thread overview]
Message-ID: <20221206214207.GA1368357@bhelgaas> (raw)
In-Reply-To: <20220928105946.12469-9-chenzhuo.1@bytedance.com>
Hi Zhuo,
On Wed, Sep 28, 2022 at 06:59:45PM +0800, Zhuo Chen wrote:
> When state is pci_channel_io_frozen in pcie_do_recovery(), the
> severity is fatal and fatal error status should be cleared.
> So add pci_aer_clear_fatal_status().
>
> Signed-off-by: Zhuo Chen <chenzhuo.1@bytedance.com>
> ---
> drivers/pci/pcie/err.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index f80b21244ef1..b46f1d36c090 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -241,7 +241,10 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_walk_bridge(bridge, report_resume, &status);
>
> pcie_clear_device_status(dev);
> - pci_aer_clear_nonfatal_status(dev);
> + if (state == pci_channel_io_frozen)
> + pci_aer_clear_fatal_status(dev);
> + else
> + pci_aer_clear_nonfatal_status(dev);
I'm confused. It seems like we certainly need to clear fatal errors
after they occur *somewhere*, and if we don't, surely this would be a
very obvious issue. But you didn't mention this being a bug fix, so I
assume it's more of a cleanup.
If it *is* a bug fix, please say that and give a hint about what the
bug looks like, e.g., what sort of messages a user might see.
If it's not a bug fix, I don't understand how AER fatal errors get
cleared today. The PCI_ERR_UNCOR_STATUS bits are sticky, so they're
not cleared by a reset. In the current tree, these are the only
places I see that clear AER fatal errors:
pci_init_capabilities
pci_aer_init # once at device enumeration
pci_aer_clear_status
pci_aer_raw_clear_status
pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, status)
aer_probe
aer_enable_rootport # once at Root Port enumeration
pci_write_config_dword(pdev, aer + PCI_ERR_UNCOR_STATUS, reg32)
dpc_process_error # after DPC triggered
pci_aer_clear_fatal_status
pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, status)
edr_handle_event # after EDR event
pci_aer_raw_clear_status
pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, status)
pci_restore_state # after reset or PM sleep/resume
pci_aer_clear_status
pci_aer_raw_clear_status
pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, status)
The only one that could clear errors after an AER error (not DPC or
EDR), would be the pci_restore_state() in the reset path. If the
current code relies on that, I'd say that's a pretty non-obvious
dependency.
> pci_info(bridge, "device recovery successful\n");
> return status;
> --
> 2.30.1 (Apple Git-130)
>
next prev parent reply other threads:[~2022-12-06 21:42 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-28 10:59 [PATCH v3 0/9] PCI/AER: Fix and optimize usage of status clearing api Zhuo Chen
2022-09-28 10:59 ` [PATCH v3 1/9] PCI/AER: Add pci_aer_clear_uncorrect_error_status() to PCI core Zhuo Chen
2023-03-15 21:29 ` Bjorn Helgaas
2022-09-28 10:59 ` [PATCH v3 2/9] PCI/DPC: Use pci_aer_clear_uncorrect_error_status() to clear uncorrectable error status Zhuo Chen
2022-09-28 10:59 ` [PATCH v3 3/9] NTB: Remove pci_aer_clear_nonfatal_status() call Zhuo Chen
2022-09-28 11:03 ` Serge Semin
2022-12-06 18:09 ` Bjorn Helgaas
2022-12-06 21:41 ` Serge Semin
2023-03-15 21:31 ` Bjorn Helgaas
2022-09-28 10:59 ` [PATCH v3 4/9] scsi: lpfc: Change to use pci_aer_clear_uncorrect_error_status() Zhuo Chen
2022-12-06 22:13 ` Bjorn Helgaas
2023-03-15 21:35 ` Bjorn Helgaas
2023-03-30 23:43 ` Justin Tee
2022-09-28 10:59 ` [PATCH v3 5/9] PCI/AER: Unexport pci_aer_clear_nonfatal_status() Zhuo Chen
2022-09-28 10:59 ` [PATCH v3 6/9] PCI/AER: Move check inside pcie_clear_device_status() Zhuo Chen
2022-09-28 10:59 ` [PATCH v3 7/9] PCI/AER: Use pcie_aer_is_native() to judge whether OS owns AER Zhuo Chen
2022-09-28 10:59 ` [PATCH v3 8/9] PCI/ERR: Clear fatal error status when pci_channel_io_frozen Zhuo Chen
2022-12-06 21:42 ` Bjorn Helgaas [this message]
2022-09-28 10:59 ` [PATCH v3 9/9] PCI/AER: Refine status clearing process with api Zhuo Chen
2022-09-28 11:06 ` [PATCH v3 0/9] PCI/AER: Fix and optimize usage of status clearing api Serge Semin
2022-09-28 15:54 ` [External] " Zhuo Chen
2022-11-04 17:20 ` Zhuo Chen
2022-11-24 11:55 ` Zhuo Chen
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