The patch titled Subject: loopdev: fix a deadlock has been added to the -mm tree. Its filename is loopdev-fix-a-deadlock.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Guo Chao <yan@xxxxxxxxxxxxxxxxxx> Subject: loopdev: fix a deadlock bd_mutex and lo_ctl_mutex can be held in different order. Path #1: blkdev_open blkdev_get __blkdev_get (hold bd_mutex) lo_open (hold lo_ctl_mutex) Path #2: blkdev_ioctl lo_ioctl (hold lo_ctl_mutex) lo_set_capacity (hold bd_mutex) Lockdep does not report it, because path #2 actually holds a subclass of lo_ctl_mutex. This subclass seems creep into the code by mistake. The patch author actually just mentioned it in the changelog, see commit f028f3b2 ("loop: fix circular locking in loop_clr_fd()"), also see: http://marc.info/?l=linux-kernel&m=123806169129727&w=2 Path #2 hold bd_mutex to call bd_set_size(), I've protected it with i_mutex in a previous patch, so drop bd_mutex at this site. Signed-off-by: Guo Chao <yan@xxxxxxxxxxxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Guo Chao <yan@xxxxxxxxxxxxxxxxxx> Cc: M. Hindess <hindessm@xxxxxxxxxx> Cc: Nikanth Karthikesan <knikanth@xxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/block/loop.c | 2 -- 1 file changed, 2 deletions(-) diff -puN drivers/block/loop.c~loopdev-fix-a-deadlock drivers/block/loop.c --- a/drivers/block/loop.c~loopdev-fix-a-deadlock +++ a/drivers/block/loop.c @@ -1285,11 +1285,9 @@ static int loop_set_capacity(struct loop /* the width of sector_t may be narrow for bit-shift */ sz = sec; sz <<= 9; - mutex_lock(&bdev->bd_mutex); bd_set_size(bdev, sz); /* let user-space know about the new size */ kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); - mutex_unlock(&bdev->bd_mutex); out: return err; _ Patches currently in -mm which might be from yan@xxxxxxxxxxxxxxxxxx are linux-next.patch block-use-i_size_write-in-bd_set_size.patch block-remove-redundant-check-to-bd_openers.patch loopdev-fix-a-deadlock.patch loopdev-update-block-device-size-in-loop_set_status.patch loopdev-move-common-code-into-loop_figure_size.patch loopdev-remove-an-user-triggerable-oops.patch loopdev-ignore-negative-offset-when-calculate-loop-device-size.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html