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SubjectRe: [PATCH] PCI/AER: Fix an AER enabling/disabling race
Date
Hi,

After giving this a few days thought, I think the right way is to call
pci_enable_pcie_error_reporting after portdrv probe, and prevent AER's
pci_walk_bus from enabling err reporting if the port hasn't been
probed.

I'm going to Self-NAK this and follow-up

Sorry for the noise

On Sat, 2018-09-01 at 19:06 -0600, Jon Derrick wrote:
> There is a sequence with non-ACPI root ports where the AER driver can
> enable error reporting on the tree before port drivers have bound to
> ports on the tree. The port driver assumes the AER driver will set up
> error reporting afterwards, so instead add a check if error reporting
> was set up first.
>
> Example:
> [ 343.790573] pcieport 10000:00:00.0:
> pci_disable_pcie_error_reporting
> [ 343.809812] pcieport 10000:00:00.0:
> pci_enable_pcie_error_reporting
> [ 343.819506] pci 10000:01:00.0: pci_enable_pcie_error_reporting
> [ 343.828814] pci 10000:02:00.0: pci_enable_pcie_error_reporting
> [ 343.838089] pci 10000:02:01.0: pci_enable_pcie_error_reporting
> [ 343.847478] pci 10000:02:02.0: pci_enable_pcie_error_reporting
> [ 343.856659] pci 10000:02:03.0: pci_enable_pcie_error_reporting
> [ 343.865794] pci 10000:02:04.0: pci_enable_pcie_error_reporting
> [ 343.874875] pci 10000:02:05.0: pci_enable_pcie_error_reporting
> [ 343.883918] pci 10000:02:06.0: pci_enable_pcie_error_reporting
> [ 343.892922] pci 10000:02:07.0: pci_enable_pcie_error_reporting
> [ 343.918900] pcieport 10000:01:00.0:
> pci_disable_pcie_error_reporting
> [ 343.968426] pcieport 10000:02:00.0:
> pci_disable_pcie_error_reporting
> [ 344.028179] pcieport 10000:02:01.0:
> pci_disable_pcie_error_reporting
> [ 344.091269] pcieport 10000:02:02.0:
> pci_disable_pcie_error_reporting
> [ 344.156473] pcieport 10000:02:03.0:
> pci_disable_pcie_error_reporting
> [ 344.238042] pcieport 10000:02:04.0:
> pci_disable_pcie_error_reporting
> [ 344.321864] pcieport 10000:02:05.0:
> pci_disable_pcie_error_reporting
> [ 344.411601] pcieport 10000:02:06.0:
> pci_disable_pcie_error_reporting
> [ 344.505332] pcieport 10000:02:07.0:
> pci_disable_pcie_error_reporting
> [ 344.621824] nvme 10000:06:00.0: pci_enable_pcie_error_reporting
>
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
> ---
> drivers/pci/pcie/aer.c | 1 +
> drivers/pci/pcie/portdrv_core.c | 5 ++++-
> include/linux/pci.h | 1 +
> 3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 83180ed..a4e36b6 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -1333,6 +1333,7 @@ static int set_device_error_reporting(struct
> pci_dev *dev, void *data)
> if (enable)
> pcie_set_ecrc_checking(dev);
>
> + dev->aer_configured = 1;
> return 0;
> }
>
> diff --git a/drivers/pci/pcie/portdrv_core.c
> b/drivers/pci/pcie/portdrv_core.c
> index 7c37d81..f5de554 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -224,8 +224,11 @@ static int get_port_device_capability(struct
> pci_dev *dev)
> /*
> * Disable AER on this port in case it's been
> enabled by the
> * BIOS (the AER service driver will enable it when
> necessary).
> + * Don't disable it if the AER service driver has
> already
> + * enabled it from the root port bus walking
> */
> - pci_disable_pcie_error_reporting(dev);
> + if (!dev->aer_configured)
> + pci_disable_pcie_error_reporting(dev);
> }
> #endif
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index e72ca8d..c071622 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -402,6 +402,7 @@ struct pci_dev {
> unsigned int has_secondary_link:1;
> unsigned int non_compliant_bars:1; /* Broken
> BARs; ignore them */
> unsigned int is_probed:1; /* Device
> probing in progress */
> + unsigned int aer_configured:1; /* AER
> configured for device */
> pci_dev_flags_t dev_flags;
> atomic_t enable_cnt; /* pci_enable_device has
> been called */
> [unhandled content-type:application/x-pkcs7-signature]
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