James Bottomley wrote: > On Thu, 2009-05-21 at 10:55 +0900, Tejun Heo wrote: >> James Bottomley wrote: >>> commit e8939a50466fd963eb1ba9118c34b9ffb7ff6aa6 >>> Author: Tejun Heo <tj@xxxxxxxxxx> >>> Date: Fri May 8 11:54:16 2009 +0900 >>> >>> block: implement and enforce request peek/start/fetch >>> >>> Added a BUG_ON(blk_queued_rq(req)) to the top of blk_finish_req(). >>> Unfortunately, this checks whether req->queuelist is empty. This list >>> is doing double duty both as the queue list and the tag list, so tagged >>> requests come in here with this not empty and boom (the tag list is >>> emptied by blk_queue_end_tag() lower down). >>> >>> Fix this by moving the BUG_ON to below the end tag we also seem >>> vulnerable to this in blk_requeue_request() as well. I think all uses >>> of blk_queued_rq() need auditing because the check is clearly wrong in >>> the tagged case. >>> >>> Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> >> Oops, >> >> Acked-by: Tejun Heo <tj@xxxxxxxxxx> >> >> There are also some drivers which use queuelist for internal purposes >> after dequeueing, which also screws up blk_queued_rq() test in >> addition to being questionable practice to begin with. Maybe we would >> be better off with a flag? > > Either is fine by me ... could we get some fix in, please? I'm > currently carrying this below the merge-base on the SCSI postmerge tree > to prevent my main build server oopsing under SCSI testing ... I'm a bit > surprised we haven't had more reports from linux-oops ... but you can > bet that if Jens moves libata to generic tag use, that will change ... For now, I think your patch is fine and thus the Acked-by. Jens? Thanks. -- tejun -- 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
