Re: panic: sleeping thread & bufwrite: buffer is not busy???

On Thu, Dec 11, 2008 at 02:35:01PM +0900, Randy Bush wrote:
> i386 soekris 5501
> current as of Dec 11 00:27 gmt
> 
> Unread portion of the kernel message buffer:
> Sleeping thread (tid 100054, pid 646) owns a non-sleepable lock
> panic: sleeping thread
> panic: bufwrite: buffer is not busy???
> Uptime: 2m1s
> Physical memory: 503 MB
> 
> #0  doadump () at pcpu.h:246
> #1  0xc0571f33 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:420
> #2  0xc05720f7 in panic (fmt=Variable "fmt" is not available.)
>     at /usr/src/sys/kern/kern_shutdown.c:576
> #3  0xc06fc75c in ffs_bufwrite (bp=0xc2937e20)
>     at /usr/src/sys/ufs/ffs/ffs_vfsops.c:1786
> #4  0xc05c7250 in vfs_bio_awrite (bp=0xc2937e20) at buf.h:385
> #5  0xc05cfee0 in vop_stdfsync (ap=0xc2a89b34)
>     at /usr/src/sys/kern/vfs_default.c:479
> #6  0xc0520ad3 in devfs_fsync (ap=0xc2a89b34)
>     at /usr/src/sys/fs/devfs/devfs_vnops.c:485
> #7  0xc074e50e in VOP_FSYNC_APV (vop=0xc07cc800, a=0xc2a89b34)
>     at vnode_if.c:1007
> #8  0xc06fd0a2 in ffs_sync (mp=0xc2e33c80, waitfor=2, td=0xc2c28480)
>     at vnode_if.h:529
> #9  0xc05e0803 in sync (td=0xc2c28480, uap=0x0)
>     at /usr/src/sys/kern/vfs_syscalls.c:149
> #10 0xc0571ad2 in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:312
> #11 0xc05720f7 in panic (fmt=Variable "fmt" is not available.)
>     at /usr/src/sys/kern/kern_shutdown.c:576
> #12 0xc059ec81 in propagate_priority (td=0xc2e696c0)
>     at /usr/src/sys/kern/subr_turnstile.c:222
> #13 0xc059f551 in turnstile_wait (ts=0xc2c0ee10, owner=0xc2e696c0, 
> queue=Variable "queue" is not available.)
>     at /usr/src/sys/kern/subr_turnstile.c:738
> #14 0xc0570c73 in _rw_wlock_hard (rw=0xc2cdcd80, tid=3267527808, 
> file=0x0, line=0)
>     at /usr/src/sys/kern/kern_rwlock.c:705
> #15 0xc06bdcb6 in in6_mtutimo (rock=0xc2cdcd00)
>     at /usr/src/sys/netinet6/in6_rmx.c:437
> #16 0xc0580f77 in softclock (arg=0xc07ffbe0)
>     at /usr/src/sys/kern/kern_timeout.c:398
> #17 0xc055790a in intr_event_execute_handlers (p=0xc2c257ec, ie=0xc2c22400)
>     at /usr/src/sys/kern/kern_intr.c:1134
> #18 0xc0558933 in ithread_loop (arg=0xc2c07ba0)
>     at /usr/src/sys/kern/kern_intr.c:1147
> #19 0xc0555cb6 in fork_exit (callout=0xc05588d0 <ithread_loop>,
>     arg=0xc2c07ba0, frame=0xc2a89d38) at /usr/src/sys/kern/kern_fork.c:821
> #20 0xc0730a50 in fork_trampoline () at 
> /usr/src/sys/i386/i386/exception.s:270

Do you have sysctl kern.sync_on_panic=1 ?
The trace looks like some problem in ipv6, panic, attempt to sync
ufs, and second panic due to locking actually turned off by the first
panic.