[PATCH v4] cxl: Force context lock during EEH flow

[Michael Ellerman]

Frederic Barrat <fbarrat at linux.vnet.ibm.com> writes:

> Le 05/04/2017 à 13:35, Vaibhav Jain a écrit :
>> During an eeh event when the cxl card is fenced and card sysfs attr
>> perst_reloads_same_image is set following warning message is seen in the
>> kernel logs:
>>
>>  [   60.622727] Adapter context unlocked with 0 active contexts
>>  [   60.622762] ------------[ cut here ]------------
>>  [   60.622771] WARNING: CPU: 12 PID: 627 at
>>  ../drivers/misc/cxl/main.c:325 cxl_adapter_context_unlock+0x60/0x80 [cxl]
>>
>> Even though this warning is harmless, it clutters the kernel log
>> during an eeh event. This warning is triggered as the EEH callback
>> cxl_pci_error_detected doesn't obtain a context-lock before forcibly
>> detaching all active context and when context-lock is released during
>> call to cxl_configure_adapter from cxl_pci_slot_reset, a warning in
>> cxl_adapter_context_unlock is triggered.
>>
>> To fix this warning, we acquire the adapter context-lock via
>> cxl_adapter_context_lock() in the eeh callback
>> cxl_pci_error_detected() once all the virtual AFU PHBs are notified
>> and their contexts detached. The context-lock is released in
>> cxl_pci_slot_reset() after the adapter is successfully reconfigured
>> and before we call slot_reset callback on slice attached device-drivers.
>>
>> Cc: stable at vger.kernel.org
>> Fixes: 70b565bbdb91("cxl: Prevent adapter reset if an active context exists")
>> Reported-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
>> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>
>> ---
>
> Pending test result from cxl-flash:
> Acked-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>

Still pending ... ?

cheers