On Wed, Jul 13, 2016 at 9:38 AM, Ilya Dryomov <idryomov@xxxxxxxxx> wrote: > On Wed, Jul 13, 2016 at 2:38 AM, Patrick McLean <patrickm@xxxxxxxxxx> wrote: >> On Sat, Jul 9, 2016 at 7:30 AM, Ilya Dryomov <idryomov@xxxxxxxxx> wrote: >>> On Fri, Jul 8, 2016 at 10:30 PM, Patrick McLean <patrickm@xxxxxxxxxx> wrote: >>>> On Fri, Jul 8, 2016 at 11:46 AM, Ilya Dryomov <idryomov@xxxxxxxxx> wrote: >>>>> On Fri, Jul 8, 2016 at 7:51 PM, Patrick McLean <patrickm@xxxxxxxxxx> wrote: >>>>>> On Fri, Jul 8, 2016 at 4:40 AM, Ilya Dryomov <idryomov@xxxxxxxxx> wrote: >>>>>>> On Fri, Jul 8, 2016 at 3:28 AM, Patrick McLean <patrickm@xxxxxxxxxx> wrote: >>>>>>>> This is on linus git master as of 2016/07/01 >>>>>>>> >>>>>>>> These appear to be two separate deadlocks, one on a a map operation, >>>>>>>> and one on an unmap operation. We can reproduce these pretty >>>>>>>> regularly, but it seems like there is some sort of race condition, as >>>>>>>> it happens no where near every time. >>>>>>>> >>>>>> >>>>>>> >>>>>>> It's a single deadlock between "rbd map" and a kworker thread, a later >>>>>>> "rbd unmap" is just a victim. >>>>>>> >>>>>>> Are you mapping the same image more than once? >>>>>>> >>>>>> >>>>>> We shouldn't be, there is a higher-level locking system that is >>>>>> supposed to prevent that. >>>>> >>>>> It's actually allowed, I'm just trying to get an idea of what was going >>>>> on. >>>>> >>>>> I spoke too soon. The trace of pid 14109 is inconsistent - the entries >>>>> in the middle don't make sense. Do you have a different set of traces >>>>> or are they all the same? >>>> >>>> Here is another backtrace. It seems that once it happens to a >>>> particular image once, it always does the same thing. We have not >>>> figured out what triggers the first hang. >>>> >>>> # grep -C 40 rbd /proc/*/stack >>>> /proc/5295/stack-[<ffffffff8111c7c4>] __queue_work+0x144/0x420 >>>> /proc/5295/stack-[<ffffffff8112c1c0>] default_wake_function+0x0/0x10 >>>> /proc/5295/stack:[<ffffffffa01621ee>] >>>> rbd_obj_method_sync.constprop.48+0x1be/0x290 [rbd] >>>> /proc/5295/stack:[<ffffffffa0162aea>] rbd_dev_header_info+0x15a/0x930 [rbd] >>>> /proc/5295/stack:[<ffffffffa0163450>] rbd_watch_cb+0x0/0xa0 [rbd] >>>> /proc/5295/stack:[<ffffffffa0163586>] >>>> rbd_dev_image_probe.part.42+0x96/0x910 [rbd] >>>> /proc/5295/stack:[<ffffffffa016240e>] rbd_dev_image_id+0x14e/0x1b0 [rbd] >>>> /proc/5295/stack:[<ffffffffa016428f>] do_rbd_add.isra.43+0x48f/0xbb0 [rbd] >>>> /proc/5295/stack-[<ffffffff8123ba27>] __kmalloc+0x27/0x170 >>>> /proc/5295/stack-[<ffffffff812b7f3a>] kernfs_fop_write+0x10a/0x190 >>>> /proc/5295/stack-[<ffffffff8124dc63>] __vfs_write+0x23/0x120 >>>> /proc/5295/stack-[<ffffffff8124e8f3>] vfs_write+0xb3/0x1a0 >>>> /proc/5295/stack-[<ffffffff8124fbd2>] SyS_write+0x42/0xa0 >>>> /proc/5295/stack-[<ffffffff81816f72>] entry_SYSCALL_64_fastpath+0x1a/0xa4 >>>> /proc/5295/stack-[<ffffffffffffffff>] 0xffffffffffffffff >>>> >>>> # ps aux | grep 5295 >>>> root 5295 0.0 0.0 246704 10352 pts/4 Sl+ 20:20 0:00 rbd >>>> map --pool XXXXXXX XXXXXXXX >>> >>> Anything in dmesg? It looks like rbd map is waiting for a reply to one >>> of the header read-in requests and is never woken up. rbd map holds >>> a semaphore, blocking the kworker, which blocks rbd unmap. >>> >>> Can you set "debug ms = 1" on all OSDs and try to reproduce? >>> I'd also like to see the content of /sys/kernel/debug/ceph/*/osdc when >>> it happens again. >>> >> >> Here is the contents of the osdc debug file on a machine that had been >> in that state for 3 days. >> >> # cat /sys/kernel/debug/ceph/*/osdc >> REQUESTS 1 homeless 0 >> 7 osd38 4.27a8d388 [38,16,47]/38 [38,16,47]/38 >> rbd_header.bea4a16ebd6a9a 0x400011 1 0'0 call >> LINGER REQUESTS >> 1 osd38 4.27a8d388 [38,16,47]/38 [38,16,47]/38 >> rbd_header.bea4a16ebd6a9a 0x24 0 WC/0 > > OK, so it's waiting for a reply. Do you have a debug ms = 1 log for > osd38? I've filed http://tracker.ceph.com/issues/16630. Thanks, Ilya -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
