2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: James Bottomley <james.bottom...@hansenpartnership.com> [ upstream commit bfe159a51203c15d23cb3158fffdc25ec4b4dda1 ] USB surprise removal of sr is triggering an oops in scsi_dispatch_command(). What seems to be happening is that USB is hanging on to a queue reference until the last close of the upper device, so the crash is caused by surprise remove of a mounted CD followed by attempted unmount. The problem is that USB doesn't issue its final commands as part of the SCSI teardown path, but on last close when the block queue is long gone. The long term fix is probably to make sr do the teardown in the same way as sd (so remove all the lower bits on ejection, but keep the upper disk alive until last close of user space). However, the current oops can be simply fixed by not allowing any commands to be sent to a dead queue. Cc: sta...@kernel.org Signed-off-by: James Bottomley <jbottom...@parallels.com> Signed-off-by: Andi Kleen <a...@linux.intel.com> Index: linux-2.6.35.y/block/blk-core.c =================================================================== --- linux-2.6.35.y.orig/block/blk-core.c +++ linux-2.6.35.y/block/blk-core.c @@ -893,6 +893,9 @@ struct request *blk_get_request(struct r { struct request *rq; + if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) + return NULL; + BUG_ON(rw != READ && rw != WRITE); spin_lock_irq(q->queue_lock); Index: linux-2.6.35.y/block/blk-exec.c =================================================================== --- linux-2.6.35.y.orig/block/blk-exec.c +++ linux-2.6.35.y/block/blk-exec.c @@ -50,6 +50,13 @@ void blk_execute_rq_nowait(struct reques { int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; + if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { + rq->errors = -ENXIO; + if (rq->end_io) + rq->end_io(rq, rq->errors); + return; + } + rq->rq_disk = bd_disk; rq->end_io = done; WARN_ON(irqs_disabled()); Index: linux-2.6.35.y/drivers/scsi/scsi_lib.c =================================================================== --- linux-2.6.35.y.orig/drivers/scsi/scsi_lib.c +++ linux-2.6.35.y/drivers/scsi/scsi_lib.c @@ -215,6 +215,8 @@ int scsi_execute(struct scsi_device *sde int ret = DRIVER_ERROR << 24; req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); + if (!req) + return ret; if (bufflen && blk_rq_map_kern(sdev->request_queue, req, buffer, bufflen, __GFP_WAIT)) _______________________________________________ stable mailing list stable@linux.kernel.org http://linux.kernel.org/mailman/listinfo/stable