On Tue, Jan 10, 2017 at 07:22:24PM -0600, Doug Goldstein wrote: > On 1/10/17 10:01 AM, Stefan Hajnoczi wrote: > > On Mon, Jan 09, 2017 at 01:08:53PM +0000, Dr. David Alan Gilbert wrote: > >> copying in Stefan since it's his commit. > > > > I can't reproduce the assertion failure. > > > > Are you able to provide a backtrace (e.g. launch QEMU under gdb and then > > use the 'bt' command after the assertion failure is raised)? > > > > Thanks, > > Stefan > > > > #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:58 > #1 0x00007ffff44db3ea in __GI_abort () at abort.c:89 > #2 0x00007ffff44d1bb7 in __assert_fail_base (fmt=<optimized out>, > assertion=assertion@entry=0x555555ae8e8a "vq->notification_disabled > > 0", > file=file@entry=0x555555ae89c0 > "/home/doug/work/qemu/hw/virtio/virtio.c", > line=line@entry=215, > function=function@entry=0x555555ae9630 <__PRETTY_FUNCTION__.43707> > "virtio_queue_set_notification") at assert.c:92 > #3 0x00007ffff44d1c62 in __GI___assert_fail ( > assertion=assertion@entry=0x555555ae8e8a "vq->notification_disabled > > 0", > file=file@entry=0x555555ae89c0 > "/home/doug/work/qemu/hw/virtio/virtio.c", > line=line@entry=215, > function=function@entry=0x555555ae9630 <__PRETTY_FUNCTION__.43707> > "virtio_queue_set_notification") at assert.c:101 > #4 0x00005555557f25d6 in virtio_queue_set_notification (vq=0x55555666aa90, > enable=enable@entry=1) at /home/doug/work/qemu/hw/virtio/virtio.c:215 > #5 0x00005555557dc311 in virtio_net_has_buffers (q=<optimized out>, > q=<optimized out>, bufsize=102) > at /home/doug/work/qemu/hw/net/virtio-net.c:1008 > #6 virtio_net_receive (nc=<optimized out>, buf=0x555557386b88 "", size=102) > at /home/doug/work/qemu/hw/net/virtio-net.c:1148
Thanks, it's a legitimate bug. This code still assumes virtio_queue_set_notification() calls are idempotent. It needs to be updated to support nested callers (e.g. virtqueue polling and virtio-net). I'll send a patch to address this and CC you. Stefan
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