(9.2) panic under disk load (gam_server / knlist_remove_kq)

[Patrick Lamaiziere]

Le Sun, 14 Jul 2013 11:59:53 +0200,
Patrick Lamaiziere <patfbsd at davenulle.org> a écrit :

Hello,

> 9.2 PRERELEASE (today) / amd64
> 
> Hello,
> 
> I'm seeing a panic while trying to build a poudriere repository.
> 
> As far I can see it always happens when gam_server is started (ie
> xfce is running) and under disk load (poudriere bulk build) :
> (That is something new, the box was pretty stable)
> 
> the complete crash dump (core.0.txt) is here:
> http://user.lamaiziere.net/patrick/panic_gam_server.txt

With WITNESS and ASSERTION on, I see a warning that looks related :

Jul 14 16:23:29 roxette kernel: WARNING: destroying knlist w/ knotes on it!

and the box panics just after this.

Also there are too LOR just before the panic, I don't know it there are related or not :

Jul 14 16:23:29 roxette kernel: lock order reversal:
Jul 14 16:23:29 roxette kernel: 1st 0xfffffe0013335878 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:1240
Jul 14 16:23:29 roxette kernel: 2nd 0xfffffe00495a5488 syncer (syncer) @ /usr/src/sys/kern/vfs_subr.c:2335
Jul 14 16:23:29 roxette kernel: KDB: stack backtrace:
Jul 14 16:23:29 roxette kernel: #0 0xffffffff8094bc36 at kdb_backtrace+0x66
Jul 14 16:23:29 roxette kernel: #1 0xffffffff809603be at _witness_debugger+0x2e
Jul 14 16:23:29 roxette kernel: #2 0xffffffff80961a95 at witness_checkorder+0x865
Jul 14 16:23:29 roxette kernel: #3 0xffffffff808f8e21 at __lockmgr_args+0x1161
Jul 14 16:23:29 roxette kernel: #4 0xffffffff8099f739 at vop_stdlock+0x39
Jul 14 16:23:29 roxette kernel: #5 0xffffffff80d93593 at VOP_LOCK1_APV+0xe3
Jul 14 16:23:29 roxette kernel: #6 0xffffffff809c0727 at _vn_lock+0x47
Jul 14 16:23:29 roxette kernel: #7 0xffffffff809b42d8 at vputx+0x328
Jul 14 16:23:29 roxette kernel: #8 0xffffffff809a88d4 at dounmount+0x294
Jul 14 16:23:29 roxette kernel: #9 0xffffffff809a914e at sys_unmount+0x3ce
Jul 14 16:23:29 roxette kernel: #10 0xffffffff80cec439 at amd64_syscall+0x2f9
Jul 14 16:23:29 roxette kernel: #11 0xffffffff80cd6d57 at Xfast_syscall+0xf7
Jul 14 16:23:29 roxette kernel: lock order reversal:
Jul 14 16:23:29 roxette kernel: 1st 0xfffffe006e1eac68 ufs (ufs) @ /usr/src/sys/modules/nullfs/../../fs/nullfs/null_vnops.c:620
Jul 14 16:23:29 roxette kernel: 2nd 0xffffffff813ebda0 allproc (allproc) @ /usr/src/sys/kern/kern_descrip.c:2822
Jul 14 16:23:29 roxette kernel: KDB: stack backtrace:
Jul 14 16:23:29 roxette kernel: #0 0xffffffff8094bc36 at kdb_backtrace+0x66
Jul 14 16:23:29 roxette kernel: #1 0xffffffff809603be at _witness_debugger+0x2e
Jul 14 16:23:29 roxette kernel: #2 0xffffffff80961a95 at witness_checkorder+0x865
Jul 14 16:23:29 roxette kernel: #3 0xffffffff8091b1fa at _sx_slock+0x5a
Jul 14 16:23:29 roxette kernel: #4 0xffffffff808d30ff at mountcheckdirs+0x3f
Jul 14 16:23:29 roxette kernel: #5 0xffffffff809a891f at dounmount+0x2df
Jul 14 16:23:29 roxette kernel: #6 0xffffffff809a914e at sys_unmount+0x3ce
Jul 14 16:23:29 roxette kernel: #7 0xffffffff80cec439 at amd64_syscall+0x2f9
Jul 14 16:23:29 roxette kernel: #8 0xffffffff80cd6d57 at Xfast_syscall+0xf7
Jul 14 16:23:29 roxette kernel: WARNING: destroying knlist w/ knotes on it!

Thanks, regards