Avoid that the code for requeueing SCSI requests triggers a crash by making sure that that code isn't scheduled anymore after a device has been removed. Also, source code inspection of __scsi_remove_device() revealed a race condition in this function: no new SCSI requests must be accepted for a SCSI device after device removal started. Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> Reviewed-by: Mike Christie <michaelc@xxxxxxxxxxx> Acked-by: Tejun Heo <tj@xxxxxxxxxx> Cc: James Bottomley <JBottomley@xxxxxxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Joe Lawrence <jdl1291@xxxxxxxxx> Cc: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxx> --- drivers/scsi/scsi_lib.c | 7 ++++--- drivers/scsi/scsi_sysfs.c | 11 +++++++++-- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index fac475b..13c7455 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -155,13 +155,14 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) /* * Requeue this command. It will go before all other commands - * that are already in the queue. + * that are already in the queue. Schedule requeue work under + * lock such that the kblockd_schedule_work() call happens + * before blk_cleanup_queue() finishes. */ spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, cmd->request); - spin_unlock_irqrestore(q->queue_lock, flags); - kblockd_schedule_work(q, &device->requeue_work); + spin_unlock_irqrestore(q->queue_lock, flags); } /* diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 42c35ff..efffc92 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -966,13 +966,20 @@ void __scsi_remove_device(struct scsi_device *sdev) device_del(dev); } else put_device(&sdev->sdev_dev); + + /* + * Stop accepting new requests and wait until all queuecommand() and + * scsi_run_queue() invocations have finished before tearing down the + * device. + */ scsi_device_set_state(sdev, SDEV_DEL); + blk_cleanup_queue(sdev->request_queue); + cancel_work_sync(&sdev->requeue_work); + if (sdev->host->hostt->slave_destroy) sdev->host->hostt->slave_destroy(sdev); transport_destroy_device(dev); - /* Freeing the queue signals to block that we're done */ - blk_cleanup_queue(sdev->request_queue); put_device(dev); } -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
