Panic on BETA1 in the ZFS subsystem

[Andriy Gapon]

On 20/07/2016 17:26, Karl Denninger wrote:
> #185 0xffffffff8222955d in zio_vdev_io_start (zio=0xfffff80108754770)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:2870
> #186 0xffffffff82225d96 in zio_execute (zio=<value optimized out>)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:1556
> #187 0xffffffff8220c72d in vdev_queue_io_done (zio=<value optimized out>)
>     at
> /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c:887
> #188 0xffffffff82229719 in zio_vdev_io_done (zio=0xfffff804cfdf7770)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:2895
> #189 0xffffffff82225d96 in zio_execute (zio=<value optimized out>)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:1556
> #190 0xffffffff8222955d in zio_vdev_io_start (zio=0xfffff804cfdf7770)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:2870
> #191 0xffffffff82225d96 in zio_execute (zio=<value optimized out>)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:1556
> #192 0xffffffff8220c72d in vdev_queue_io_done (zio=<value optimized out>)
>     at
> /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c:887
> #193 0xffffffff82229719 in zio_vdev_io_done (zio=0xfffff801469a13b8)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:2895
> #194 0xffffffff82225d96 in zio_execute (zio=<value optimized out>)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:1556
> #195 0xffffffff8222955d in zio_vdev_io_start (zio=0xfffff801469a13b8)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:2870
> #196 0xffffffff82225d96 in zio_execute (zio=<value optimized out>)
>     at /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c:1556
> #197 0xffffffff8220c72d in vdev_queue_io_done (zio=<value optimized out>)
>     at
> /usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_queue.c:887
> #198 0xffffffff82229719 in zio_vdev_io_done (zio=0xfffff805dcd9d3b8)

I see how this pseudo-recursion can happen in theory, but not why it has
happened.  It would interesting to see 3 or 4 of zio-s printed,
including the top-most one at 0xfffff805dcd9d3b8.

Something like:

set print pretty
p *zio
p *zio->io_vd
p *zio->io_vd->vdev_ops

in several frames.

-- 
Andriy Gapon