On Thu, May 22, 2014 at 10:49:18PM +0200, Marcin Gibuła wrote: > This is backtrace of qemu process: > > (gdb) thread apply all backtrace
[...] a bunch of rbd threads, vnc worker thread, QEMU worker threads > Thread 1 (Thread 0x7f699bfcd900 (LWP 13647)): > #0 0x00007f6998020286 in ppoll () from /lib64/libc.so.6 > #1 0x00007f699c1f3d9b in ppoll (__ss=0x0, __timeout=0x0, __nfds=<optimized > out>, __fds=<optimized out>) at /usr/include/bits/poll2.h:77 > #2 qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>, > timeout=<optimized out>) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/qemu-timer.c:311 > #3 0x00007f699c0877e0 in aio_poll (ctx=0x7f699e4c9c00, > blocking=blocking@entry=true) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/aio-posix.c:221 > #4 0x00007f699c095c0a in bdrv_drain_all () at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/block.c:1805 QEMU is waiting for all block I/O requests to complete. I wonder if there is some weird interaction with rbd here, which is why this never completes. In gdb you can iterate over bdrv_states to inspect the open BlockDriverState structs. Each BDS struct has a tracked_requests list and bdrv_drain_all() is waiting for this pending requests list to become empty. If you see a pending request on a RADOS block device (rbd) then it would be good to dig deeper into QEMU's block/rbd.c driver to see why it's not completing that request. Are you using qcow2 on top of rbd? > #5 0x00007f699c09c87e in bdrv_close (bs=bs@entry=0x7f699f0bc520) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/block.c:1695 > #6 0x00007f699c09c5fa in bdrv_delete (bs=0x7f699f0bc520) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/block.c:1978 > #7 bdrv_unref (bs=0x7f699f0bc520) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/block.c:5198 > #8 0x00007f699c09c812 in bdrv_drop_intermediate > (active=active@entry=0x7f699ebfd330, top=top@entry=0x7f699f0bc520, > base=base@entry=0x7f699eec43d0) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/block.c:2567 > #9 0x00007f699c0a1963 in commit_run (opaque=0x7f699f17dcc0) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/block/commit.c:144 > #10 0x00007f699c0e0dca in coroutine_trampoline (i0=<optimized out>, > i1=<optimized out>) at > /var/tmp/portage/app-emulation/qemu-2.0.0_rc2/work/qemu-2.0.0-rc2/coroutine-ucontext.c:118 > #11 0x00007f6997f859f0 in ?? () from /lib64/libc.so.6 > #12 0x00007fffdbe06750 in ?? () > #13 0x0000000000000000 in ?? ()
