Re: [PATCH v2 1/2] rt2x00usb: fix rx queue hang

[Soeren Moch]

On 15.07.19 10:48, Kalle Valo wrote:
> Soeren Moch <smoch@xxxxxx> writes:
>
>> Since commit ed194d136769 ("usb: core: remove local_irq_save() around
>>  ->complete() handler") the handler rt2x00usb_interrupt_rxdone() is
>> not running with interrupts disabled anymore. So this completion handler
>> is not guaranteed to run completely before workqueue processing starts
>> for the same queue entry.
>> Be sure to set all other flags in the entry correctly before marking
>> this entry ready for workqueue processing. This way we cannot miss error
>> conditions that need to be signalled from the completion handler to the
>> worker thread.
>> Note that rt2x00usb_work_rxdone() processes all available entries, not
>> only such for which queue_work() was called.
>>
>> This patch is similar to what commit df71c9cfceea ("rt2x00: fix order
>> of entry flags modification") did for TX processing.
>>
>> This fixes a regression on a RT5370 based wifi stick in AP mode, which
>> suddenly stopped data transmission after some period of heavy load. Also
>> stopping the hanging hostapd resulted in the error message "ieee80211
>> phy0: rt2x00queue_flush_queue: Warning - Queue 14 failed to flush".
>> Other operation modes are probably affected as well, this just was
>> the used testcase.
>>
>> Fixes: ed194d136769 ("usb: core: remove local_irq_save() around ->complete() handler")
>> Cc: stable@xxxxxxxxxxxxxxx # 4.20+
>> Signed-off-by: Soeren Moch <smoch@xxxxxx>
> I'll queue this for v5.3.
>
OK, thanks,
Soeren