misc/137852: LOR bufwait/dirhash

Nathaniel Filardo nwf at cs.jhu.edu
Sun Aug 16 19:10:04 UTC 2009

>Number:         137852
>Category:       misc
>Synopsis:       LOR bufwait/dirhash
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Aug 16 19:10:03 UTC 2009
>Originator:     Nathaniel Filardo
>Release:        -CURRENT
FreeBSD hydra.priv.oc.ietfng.org 8.0-BETA2 FreeBSD 8.0-BETA2 #2: Sun Aug 16 13:00:36 EDT 2009     root at hydra.priv.oc.ietfng.org:/systank/obj/systank/src/sys/NWFKERN  sparc64

lock order reversal:
 1st 0xea5e97f8 bufwait (bufwait) @ /systank/src/sys/kern/vfs_bio.c:2559
 2nd 0xfffff8000edea400 dirhash (dirhash) @ /systank/src/sys/ufs/ufs/ufs_dirhash.c:285
KDB: stack backtrace:
_witness_debugger() at _witness_debugger+0x38
witness_checkorder() at witness_checkorder+0xcf8
_sx_xlock() at _sx_xlock+0x9c
ufsdirhash_acquire() at ufsdirhash_acquire+0x30
ufsdirhash_add() at ufsdirhash_add+0x4
ufs_direnter() at ufs_direnter+0x75c
ufs_makeinode() at ufs_makeinode+0x4f8
ufs_create() at ufs_create+0x40
vn_open_cred() at vn_open_cred+0x1fc
vn_open() at vn_open+0x1c
kern_openat() at kern_openat+0x10c
kern_open() at kern_open+0x18
open() at open+0x14
syscall() at syscall+0x2f0
-- syscall (5, FreeBSD ELF64, open) %o7=0x104224 --
userland() at 0x404711a8
user trace: trap %o7=0x104224
pc 0x404711a8, sp 0x7fdffffb491
pc 0x101090, sp 0x7fdffffe2b1
pc 0x4020ad94, sp 0x7fdffffe371

This happened even on GENERIC, so don't mind too much that uname -a says NWFKERN instead. :)

Apologies if this is a duplicate; a quick search didn't find one, but it's possible I've missed.

What else would be helpful?
This is more or less guaranteed to happen eventually, and is triggered by any number of different things.  csup has triggered it, the dump posted above is due to a chsh command...


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