5.3-S (Mar 6) softdep stack backtrace from getdirtybuf()... problem?

[Sven Willenberger]

Brandon S. Allbery KF8NH presumably uttered the following on 04/10/05 15:16:
> I have twice so far had the kernel syslog a stack backtrace with no
> other information.  Inspection of the kernel source, to the best of my
> limited understanding, suggests that getdirtybuf() was handed a buffer
> without an associated vnode.  Kernel config file and make.conf attached.
> 
> Should I be concerned?
> 
> Note that this system is an older 600MHz Athlon with only 256MB RAM, and
> both times this triggered it was thrashing quite a bit (that's more or
> less its usual state...).
> 
> KDB: stack backtrace:
> kdb_backtrace(c06fbf78,2,c63ca26c,0,22) at kdb_backtrace+0x2e
> getdirtybuf(d3196bac,0,1,c63ca26c,1) at getdirtybuf+0x2b
> flush_deplist(c1a8544c,1,d3196bd4,d3196bd8,0) at flush_deplist+0x49
> flush_inodedep_deps(c11eb800,5858f,c1ea723c,d3196c34,c052952f) at flush_inodedep_deps+0x9e
> softdep_sync_metadata(d3196ca4,c1ea7210,50,c06c9a19,0) at softdep_sync_metadata+0x9d
> ffs_fsync(d3196ca4,0,0,0,0) at ffs_fsync+0x487
> fsync(c1b367d0,d3196d14,4,c10f9700,0) at fsync+0x196
> syscall(2f,2f,2f,8327600,5e) at syscall+0x300
> Xint0x80_syscall() at Xint0x80_syscall+0x1f
> --- syscall (95, FreeBSD ELF32, fsync), eip = 0x29152d6f, esp = 0xbf5a8d5c, ebp = 0xbf5a8d78 ---
> 
> FreeBSD rushlight.kf8nh.com 5.3-STABLE FreeBSD 5.3-STABLE #0: Sun Mar  6 02:56:16 EST 2005     root at rushlight.kf8nh.com:/usr/src/sys/i386/compile/RUSHLIGHT  i386
> 
> 

I used to see this on a regular basis on several machines I had running 
early 5 through 5.2 releases and it seemed to have gone away (for me) 
with the 5.3 release(s). I never did hear of a definitive resolution for 
this issue; your backtrace is alarmingly similar to the one that I had seen.

http://lists.freebsd.org/pipermail/freebsd-current/2004-July/031576.html

Sven