panic: _sx_xlock_hard: recursed on non-recursive sx zfsvfs->z_hold_mtx[i] @ ...cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c:1407

[Florian Smeets]

Hi,

I hit the above mentioned panic quite frequently on recent versions of
head (r240806). This happens when building packages in the ports
tinderbox which uses nullfs and zfs extensively. Kib had a look at it
and suspects that his recent nullfs changes expose a bug in zfs.

The backtrace is as follows:

#0  doadump (textdump=1) at
/usr/home/flo/dev/checkouts/svn-src/sys/kern/kern_shutdown.c:266
#1  0xffffffff804c6a64 in kern_reboot (howto=260) at
/usr/home/flo/dev/checkouts/svn-src/sys/kern/kern_shutdown.c:449
#2  0xffffffff804c648a in panic (fmt=0x0) at
/usr/home/flo/dev/checkouts/svn-src/sys/kern/kern_shutdown.c:637
#3  0xffffffff804ce6e5 in _sx_xlock_hard (sx=Variable "sx" is not available.
) at /usr/home/flo/dev/checkouts/svn-src/sys/kern/kern_sx.c:523
#4  0xffffffff804ce77e in _sx_xlock (sx=Variable "sx" is not available.
) at sx.h:152
#5  0xffffffff80e17533 in zfs_zinactive (zp=0xfffffe011951ec80) at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c:1407
#6  0xffffffff80e45366 in zfs_inactive (vp=0xfffffe019bdfad90,
cr=Variable "cr" is not available.
) at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c:4590
#7  0xffffffff80e4552a in zfs_freebsd_inactive (ap=Variable "ap" is not
available.
) at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c:6102
#8  0xffffffff8070aae7 in VOP_INACTIVE_APV (vop=0xffffffff80eb5fe0,
a=0xffffff89092d3d20) at vnode_if.c:1863
#9  0xffffffff8055e3b7 in vinactive (vp=0xfffffe019bdfad90,
td=0xfffffe0017bad900) at vnode_if.h:807
#10 0xffffffff80562526 in vputx (vp=0xfffffe019bdfad90, func=2) at
/usr/home/flo/dev/checkouts/svn-src/sys/kern/vfs_subr.c:2290
#11 0xffffffff80d8a5f0 in null_reclaim (ap=Variable "ap" is not available.
) at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/nullfs/../../fs/nullfs/null_vnops.c:706
#12 0xffffffff8070a9d7 in VOP_RECLAIM_APV (vop=0xffffffff80d8b180,
a=0xffffff89092d3e60) at vnode_if.c:1926
#13 0xffffffff8055f64d in vgonel (vp=0xfffffe019bdb73e0) at vnode_if.h:830
#14 0xffffffff80561815 in vnlru_free (count=1) at
/usr/home/flo/dev/checkouts/svn-src/sys/kern/vfs_subr.c:931
#15 0xffffffff80561b1f in getnewvnode (tag=0xffffffff80eae0f3 "zfs",
mp=0xfffffe0010dc3cc0, vops=0xffffffff80eb5fe0, vpp=0xffffff89092d3f88)
    at /usr/home/flo/dev/checkouts/svn-src/sys/kern/vfs_subr.c:953
#16 0xffffffff80e168b5 in zfs_znode_cache_constructor
(buf=0xfffffe019b437af0, arg=Variable "arg" is not available.
)
    at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c:135
#17 0xffffffff80e189cc in zfs_znode_alloc (zfsvfs=0xfffffe0010de4000,
db=0xfffffe048c138000, blksz=0, obj_type=DMU_OT_SA, hdl=0xfffffe019b441cd0)
    at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c:663
#18 0xffffffff80e19b65 in zfs_mknode (dzp=0xfffffe00b84dd7d0,
vap=0xffffff89092d4740, tx=0xfffffe0303916600, cr=0xfffffe000c668e00,
flag=0, zpp=0xffffff89092d46a0, acl_ids=0xffffff89092d4670)
    at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c:1012
#19 0xffffffff80e46d6f in zfs_freebsd_create (ap=Variable "ap" is not
available.
) at
/usr/home/flo/dev/checkouts/svn-src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c:1657
#20 0xffffffff8070cef1 in VOP_CREATE_APV (vop=0xffffffff80eb5fe0,
a=0xffffff89092d47f0) at vnode_if.c:250
#21 0xffffffff8056f569 in vn_open_cred (ndp=0xffffff89092d4880,
flagp=0xffffff89092d487c, cmode=Variable "cmode" is not available.
) at vnode_if.h:109
#22 0xffffffff80569236 in kern_openat (td=0xfffffe0017bad900, fd=-100,
path=0x801c2b300 <Address 0x801c2b300 out of bounds>, pathseg=Variable
"pathseg" is not available.
)
    at /usr/home/flo/dev/checkouts/svn-src/sys/kern/vfs_syscalls.c:1134
#23 0xffffffff806b8329 in amd64_syscall (td=0xfffffe0017bad900,
traced=0) at subr_syscall.c:135
#24 0xffffffff806a2eb7 in Xfast_syscall () at
/usr/home/flo/dev/checkouts/svn-src/sys/amd64/amd64/exception.S:387
#25 0x00000008017702ec in ?? ()
Previous frame inner to this frame (corrupt stack?)

I have the vmcore and kernel symbols, so if someone wants to know more I
should be able to provide further data.

Florian

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