On Wed, May 27 2009, Tejun Heo wrote: > 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? Yes indeed, sorry for the delay. I'll commit it. -- Jens Axboe -- 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
