On Mon, Jul 01, 2019 at 12:53:13PM +0200, Soeren Moch wrote:
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@vger.kernel.org # 4.20+ Signed-off-by: Soeren Moch smoch@web.de
Acked-by: Stanislaw Gruszka sgruszka@redhat.com