kern/73807: panic: mutex nfsd_mtx not owned in NFS server
sysmaint at filbert.contek.com
Thu Nov 11 02:10:30 PST 2004
>Synopsis: panic: mutex nfsd_mtx not owned in NFS server
>Arrival-Date: Thu Nov 11 10:10:21 GMT 2004
>Originator: Douglas Wells
>Release: FreeBSD 5.3
System: FreeBSD filbert.contek.com 5.2.1-RELEASE-p11 FreeBSD 5.2.1-RELEASE-p11 #2: Wed Nov 10 16:59:00 EST 2004 root at filbert.contek.com:/var/obj/usr/src.5.2.1/sys/FILBERT i386
The problem environment is the same as the system above
except that the OS is FreeBSD 5.3 - cvsup updated (RELENG_5_3)
November 9 evening. Updated from 5.2.1 via recommended
buildworld / buildkernel sequence.
The FreeBSD system panics when I attempt to boot a diskless
Sun 3 that mounts all filesystems from the FreeBSD system.
The problem began as a NULL pointer dereference when I
used a custom SMP kernel. The same NULL pointer deference
occurred when I repeated the problem with a stock GENERIC
kernel compiled from the same sources. I then ran a variant
of GENERIC with the following options:
Repeating the bootload of the Sun 3 led to the following
panic, which I presume to be due to the same cause as the
NULL pointer deference: (This information is retyped.)
panic: mutex nfsd_mtx not owned at ... nfs_serv.c:4493
mtx_assert+5c (c08d97c0, 1, c08160f7, 118d)
nfsrv_access+28 (c7217420, 80, c2142180, 0, c1a79190)
nfsrv_create+84c (c22142100, c1d62d80, c1a79190, d5469c98, c08d97c0)
nfssvc_nfsd+3d5 (c1a79190, c08067a3, 12b, c1c360bc, c1c36000)
nfssvc+18c (c1a79190, d5469d14, 2, 0, 296)
syscall+213 (2f, 2f, 2f, bf??eec4, 4)
I repeated the experiment several times and generally the
addresses and thread id vary from run to run. The exceptions
are the last arg (c08d97c0) to nfsrv_create and the second
arg (c08067a3) to nfssvc_nfsd.
I believe that the problem is due to the system mishandling
RPC requests for mounts of regular files (mountd(8) -r):
- If I remove the -r option to mountd and attempt to
boot the Sun 3, the FreeBSD system does not panic (but
of course, the Sun 3 does not boot properly).
- If I leave the Sun 3 up from having booted from a 5.2.1
system, the FreeBSD system panics very soon after it
starts up system daemons. (Note that the mountd daemon
would not be invoked in this case. The NFS request
would use information retained from the previous (5.2.1)
- This bootload operationg has previously worked regularly
on both 5.1 and 5.2+.
- I have modified mountd to support v2 mounts, but I
disabled my extensions during at least some of the
tests above. These extensions are simple.
- Note that the hardware system has 2 AMD Athlon CPUs,
but I understand that by not including the SMP kernel
option, the OS behaves as though the hardware were
This happens repeatably whenever I attempt to bootload the
Sun 3. I presume that sending the NFS server an I/O request
for any regular file that is being treated as a mount
point would also trigger this problem.
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