frequent panics on 9.2-RELEASE

[Will Parsons]

A few days ago, I started to get frequent panics on a laptop running
9.2-RELEASE.  The message is:

panic: ffs_valloc: dup alloc

and the backtrace from the core.txt file is:

KDB: stack backtrace:
#0 0xc0b1810f at kdb_backtrace+0x4f
#1 0xc0adf38f at panic+0x16f
#2 0xc0d102d4 at ffs_valloc+0x5a4
#3 0xc0d50384 at ufs_makeinode+0xa4
#4 0xc0d50c80 at ufs_create+0x30
#5 0xc0f73b02 at VOP_CREATE_APV+0xa2
#6 0xc0b8e3f6 at vn_open_cred+0x246
#7 0xc0b8e87b at vn_open+0x3b
#8 0xc0b89ccc at kern_openat+0x1ec
#9 0xc0b8a0e5 at kern_open+0x35
#10 0xc0b8a120 at sys_open+0x30
#11 0xc0f4ce53 at syscall+0x443
#12 0xc0f36661 at Xint0x80_syscall+0x21
Uptime: 7m7s
Physical memory: 2965 MB
Dumping 160 MB: 145 129 113 97 81 65 49 33 17 1

I don't really have any experience with FreeBSD kernel dumps, so I
don't know how to pick out what's important.  How do I proceed to
resolve this problem?

(Also note that I have 9.1-RELEASE installed on the same machine on a
different slice which is stable, so I think hardware problems are not
likely to be a factor.)

-- 
Will