2020-10-10 23:09:04

by Hedi Berriche

Subject: [RESEND PATCH v3 1/1] PCI/ERR: don't clobber status after reset_link()

Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
broke pcie_do_recovery(): updating status after reset_link() has the ill
side effect of causing recovery to fail if the error status is
PCI_ERS_RESULT_CAN_RECOVER or PCI_ERS_RESULT_NEED_RESET as the following
code will *never* run in the case of a successful reset_link()

177 if (status == PCI_ERS_RESULT_CAN_RECOVER) {
...
181 }

183 if (status == PCI_ERS_RESULT_NEED_RESET) {
...
192 }

For instance in the case of PCI_ERS_RESULT_NEED_RESET we end up not
calling ->slot_reset() (because we skip report_slot_reset()) thus
breaking driver (re)initialisation.

Don't clobber status with the return value of reset_link(); set status
to PCI_ERS_RESULT_RECOVERED, in case of successful link reset, if and
only if the initial value of error status is PCI_ERS_RESULT_DISCONNECT
or PCI_ERS_RESULT_NO_AER_DRIVER.

Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
Signed-off-by: Hedi Berriche <[email protected]>
Cc: Russ Anderson <[email protected]>
Cc: Kuppuswamy Sathyanarayanan <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Ashok Raj <[email protected]>
Cc: Joerg Roedel <[email protected]>

Cc: [email protected] # v5.7+
---
drivers/pci/pcie/err.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index c543f419d8f9..2730826cfd8a 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -165,10 +165,13 @@ 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_walk_bus(bus, report_frozen_detected, &status);
- status = reset_link(dev);
- if (status != PCI_ERS_RESULT_RECOVERED) {
+ if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) {
pci_warn(dev, "link reset failed\n");
goto failed;
+ } else {
+ if (status == PCI_ERS_RESULT_DISCONNECT ||
+ status == PCI_ERS_RESULT_NO_AER_DRIVER)
+ status = PCI_ERS_RESULT_RECOVERED;
}
} else {
pci_walk_bus(bus, report_normal_detected, &status);
--
2.28.0

2020-10-11 22:07:01

by Sinan Kaya

Subject: Re: [RESEND PATCH v3 1/1] PCI/ERR: don't clobber status after reset_link()

On 10/10/2020 6:16 PM, Hedi Berriche wrote:
> Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
> broke pcie_do_recovery(): updating status after reset_link() has the ill
> side effect of causing recovery to fail if the error status is
> PCI_ERS_RESULT_CAN_RECOVER or PCI_ERS_RESULT_NEED_RESET as the following
> code will *never* run in the case of a successful reset_link()
>
> 177 if (status == PCI_ERS_RESULT_CAN_RECOVER) {
> ...
> 181 }
>
> 183 if (status == PCI_ERS_RESULT_NEED_RESET) {
> ...
> 192 }
>
> For instance in the case of PCI_ERS_RESULT_NEED_RESET we end up not
> calling ->slot_reset() (because we skip report_slot_reset()) thus
> breaking driver (re)initialisation.
>
> Don't clobber status with the return value of reset_link(); set status
> to PCI_ERS_RESULT_RECOVERED, in case of successful link reset, if and
> only if the initial value of error status is PCI_ERS_RESULT_DISCONNECT
> or PCI_ERS_RESULT_NO_AER_DRIVER.
>
> Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
> Signed-off-by: Hedi Berriche <[email protected]>
> Cc: Russ Anderson <[email protected]>
> Cc: Kuppuswamy Sathyanarayanan <[email protected]>
> Cc: Bjorn Helgaas <[email protected]>
> Cc: Ashok Raj <[email protected]>
> Cc: Joerg Roedel <[email protected]>
>
> Cc: [email protected] # v5.7+
> ---
> drivers/pci/pcie/err.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index c543f419d8f9..2730826cfd8a 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -165,10 +165,13 @@ 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_walk_bus(bus, report_frozen_detected, &status);
> - status = reset_link(dev);
> - if (status != PCI_ERS_RESULT_RECOVERED) {
> + if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) {
> pci_warn(dev, "link reset failed\n");
> goto failed;
> + } else {
> + if (status == PCI_ERS_RESULT_DISCONNECT ||
> + status == PCI_ERS_RESULT_NO_AER_DRIVER)
> + status = PCI_ERS_RESULT_RECOVERED;
> }
> } else {
> pci_walk_bus(bus, report_normal_detected, &status);
>

Reviewed-by: Sinan Kaya <[email protected]>

2020-10-15 15:37:48

by Hedi Berriche

Subject: Re: [RESEND PATCH v3 1/1] PCI/ERR: don't clobber status after reset_link()

On Sun, Oct 11, 2020 at 18:56 Sinan Kaya wrote:
>On 10/10/2020 6:16 PM, Hedi Berriche wrote:
>> Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
>> broke pcie_do_recovery(): updating status after reset_link() has the ill
>> side effect of causing recovery to fail if the error status is
>> PCI_ERS_RESULT_CAN_RECOVER or PCI_ERS_RESULT_NEED_RESET as the following
>> code will *never* run in the case of a successful reset_link()
>>
>> 177 if (status == PCI_ERS_RESULT_CAN_RECOVER) {
>> ...
>> 181 }
>>
>> 183 if (status == PCI_ERS_RESULT_NEED_RESET) {
>> ...
>> 192 }
>>
>> For instance in the case of PCI_ERS_RESULT_NEED_RESET we end up not
>> calling ->slot_reset() (because we skip report_slot_reset()) thus
>> breaking driver (re)initialisation.
>>
>> Don't clobber status with the return value of reset_link(); set status
>> to PCI_ERS_RESULT_RECOVERED, in case of successful link reset, if and
>> only if the initial value of error status is PCI_ERS_RESULT_DISCONNECT
>> or PCI_ERS_RESULT_NO_AER_DRIVER.
>>
>> Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
>> Signed-off-by: Hedi Berriche <[email protected]>
>> Cc: Russ Anderson <[email protected]>
>> Cc: Kuppuswamy Sathyanarayanan <[email protected]>
>> Cc: Bjorn Helgaas <[email protected]>
>> Cc: Ashok Raj <[email protected]>
>> Cc: Joerg Roedel <[email protected]>
>>
>> Cc: [email protected] # v5.7+
>> ---
>> drivers/pci/pcie/err.c | 7 +++++--
>> 1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>> index c543f419d8f9..2730826cfd8a 100644
>> --- a/drivers/pci/pcie/err.c
>> +++ b/drivers/pci/pcie/err.c
>> @@ -165,10 +165,13 @@ 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_walk_bus(bus, report_frozen_detected, &status);
>> - status = reset_link(dev);
>> - if (status != PCI_ERS_RESULT_RECOVERED) {
>> + if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) {
>> pci_warn(dev, "link reset failed\n");
>> goto failed;
>> + } else {
>> + if (status == PCI_ERS_RESULT_DISCONNECT ||
>> + status == PCI_ERS_RESULT_NO_AER_DRIVER)
>> + status = PCI_ERS_RESULT_RECOVERED;
>> }
>> } else {
>> pci_walk_bus(bus, report_normal_detected, &status);
>>
>
>Reviewed-by: Sinan Kaya <[email protected]>

Thanks for the Reviewed-by, Sinan.

Folks,

Any further comments or is this ripe for acceptance?

Cheers,
Hedi.
--
Be careful of reading health books, you might die of a misprint.
-- Mark Twain