Hello Jens Axboe,
The patch 3582dd291788: "aoe: convert aoeblk to blk-mq" from Oct 12,
2018, leads to the following static checker warning:
block/blk-mq.c:151 blk_mq_freeze_queue_wait()
warn: sleeping in atomic context
The problem is that aoedev_downdev() can sleep now.
There are two callers of aoedev_downdev() and originally they were both
called under spinlock. One was fixed in commit 430380b4637a
("block: aoe: Fix kernel crash due to atomic sleep when exiting") but
the other is still buggy.
drivers/block/aoe/aoecmd.c
726 static void
727 rexmit_timer(struct timer_list *timer)
728 {
729 struct aoedev *d;
730 struct aoetgt *t;
731 struct aoeif *ifp;
732 struct frame *f;
733 struct list_head *head, *pos, *nx;
734 LIST_HEAD(flist);
735 register long timeout;
736 ulong flags, n;
737 int i;
738 int utgts; /* number of aoetgt descriptors (not slots) */
739 int since;
740
741 d = from_timer(d, timer, timer);
742
743 spin_lock_irqsave(&d->lock, flags);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
spin lock held.
744
745 /* timeout based on observed timings and variations */
746 timeout = rto(d);
747
748 utgts = count_targets(d, NULL);
749
750 if (d->flags & DEVFL_TKILL) {
751 spin_unlock_irqrestore(&d->lock, flags);
752 return;
753 }
754
755 /* collect all frames to rexmit into flist */
756 for (i = 0; i < NFACTIVE; i++) {
757 head = &d->factive[i];
758 list_for_each_safe(pos, nx, head) {
759 f = list_entry(pos, struct frame, head);
760 if (tsince_hr(f) < timeout)
761 break; /* end of expired frames */
762 /* move to flist for later processing */
763 list_move_tail(pos, &flist);
764 }
765 }
766
767 /* process expired frames */
768 while (!list_empty(&flist)) {
769 pos = flist.next;
770 f = list_entry(pos, struct frame, head);
771 since = tsince_hr(f);
772 n = f->waited_total + since;
773 n /= USEC_PER_SEC;
774 if (aoe_deadsecs
775 && n > aoe_deadsecs
776 && !(f->flags & FFL_PROBE)) {
777 /* Waited too long. Device failure.
778 * Hang all frames on first hash bucket for downdev
779 * to clean up.
780 */
781 list_splice(&flist, &d->factive[0]);
782 aoedev_downdev(d);
^^^^^^^^^^^^^^^^^
Sleeps in atomic if we call blk_mq_freeze_queue().
783 goto out;
784 }
785
786 t = f->t;
787 n = f->waited + since;
788 n /= USEC_PER_SEC;
789 if (aoe_deadsecs && utgts > 0
790 && (n > aoe_deadsecs / utgts || n > HARD_SCORN_SECS))
791 scorn(t); /* avoid this target */
792
regards,
dan carpenter
