On May 17, 2023 / 21:34, Ming Lei wrote: > When handling UBLK_IO_FETCH_REQ, ctx->uring_lock is grabbed first, then > ub->mutex is acquired. > > When handling UBLK_CMD_STOP_DEV or UBLK_CMD_DEL_DEV, ub->mutex is > grabbed first, then calling io_uring_cmd_done() for canceling uring > command, in which ctx->uring_lock may be required. > > Real deadlock only happens when all the above commands are issued from > same uring context, and in reality different uring contexts are often used > for handing control command and IO command. > > Fix the issue by using io_uring_cmd_complete_in_task() to cancel command > in ublk_cancel_dev(ublk_cancel_queue). > > Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx> > Closes: https://lore.kernel.org/linux-block/becol2g7sawl4rsjq2dztsbc7mqypfqko6wzsyoyazqydoasml@rcxarzwidrhk > Cc: Ziyang Zhang <ZiyangZhang@xxxxxxxxxxxxxxxxx> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Using Ziyang's new blktests test cases, I confirmed this patch avoids the failure I reported. Thanks. Tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
