panic: spin lock held too long (RELENG_8 from today)

[Mike Tancsa]

I did a buildworld on this box to bring it up to RELENG_8 for the BIND
fixes.  Unfortunately, the formerly solid box (April 13th kernel)
panic'd tonight with

Unread portion of the kernel message buffer:
spin lock 0xc0b1d200 (sched lock 1) held by 0xc5dac8a0 (tid 100107) too long
panic: spin lock held too long
cpuid = 0
Uptime: 13h30m4s
Physical memory: 2035 MB


Its a somewhat busy box taking in mail as well as backups for a few
servers over nfs.  At the time, it would have been getting about 250Mb/s
inbound on its gigabit interface.  Full core.txt file at

http://www.tancsa.com/core-jul8-2011.txt




#0  doadump () at pcpu.h:231
231     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) #0  doadump () at pcpu.h:231
#1  0xc06fd6d3 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:429
#2  0xc06fd937 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:602
#3  0xc06ed95f in _mtx_lock_spin_failed (m=0x0)
    at /usr/src/sys/kern/kern_mutex.c:490
#4  0xc06ed9e5 in _mtx_lock_spin (m=0xc0b1d200, tid=3312388992, opts=0,
    file=0x0, line=0) at /usr/src/sys/kern/kern_mutex.c:526
#5  0xc0720254 in sched_add (td=0xc5dac5c0, flags=0)
    at /usr/src/sys/kern/sched_ule.c:1119
#6  0xc07203f9 in sched_wakeup (td=0xc5dac5c0)
    at /usr/src/sys/kern/sched_ule.c:1950
#7  0xc07061f8 in setrunnable (td=0xc5dac5c0)
    at /usr/src/sys/kern/kern_synch.c:499
#8  0xc07362af in sleepq_resume_thread (sq=0xca0da300, td=0xc5dac5c0,
pri=Variable "pri" is not available.
)
    at /usr/src/sys/kern/subr_sleepqueue.c:751
#9  0xc0736e18 in sleepq_signal (wchan=0xc5fafe50, flags=1, pri=0, queue=0)
    at /usr/src/sys/kern/subr_sleepqueue.c:825
#10 0xc06b6764 in cv_signal (cvp=0xc5fafe50)
    at /usr/src/sys/kern/kern_condvar.c:422
#11 0xc08eaa0d in xprt_assignthread (xprt=Variable "xprt" is not available.
) at /usr/src/sys/rpc/svc.c:342
#12 0xc08ec502 in xprt_active (xprt=0xc95d9600) at
/usr/src/sys/rpc/svc.c:378
#13 0xc08ee051 in svc_vc_soupcall (so=0xc6372ce0, arg=0xc95d9600,
waitflag=1)
    at /usr/src/sys/rpc/svc_vc.c:747
#14 0xc075bbb1 in sowakeup (so=0xc6372ce0, sb=0xc6372d34)
    at /usr/src/sys/kern/uipc_sockbuf.c:191
#15 0xc08447bc in tcp_do_segment (m=0xcaa8d200, th=0xca6aa824,
so=0xc6372ce0,
    tp=0xc63b4d20, drop_hdrlen=52, tlen=1448, iptos=0 '\0', ti_locked=2)
    at /usr/src/sys/netinet/tcp_input.c:1775
#16 0xc0847930 in tcp_input (m=0xcaa8d200, off0=20)
    at /usr/src/sys/netinet/tcp_input.c:1329
#17 0xc07ddaf7 in ip_input (m=0xcaa8d200)
    at /usr/src/sys/netinet/ip_input.c:787
#18 0xc07b8859 in netisr_dispatch_src (proto=1, source=0, m=0xcaa8d200)
    at /usr/src/sys/net/netisr.c:859
#19 0xc07b8af0 in netisr_dispatch (proto=1, m=0xcaa8d200)
    at /usr/src/sys/net/netisr.c:946
#20 0xc07ae5e1 in ether_demux (ifp=0xc56ed800, m=0xcaa8d200)
    at /usr/src/sys/net/if_ethersubr.c:894
#21 0xc07aeb5f in ether_input (ifp=0xc56ed800, m=0xcaa8d200)
    at /usr/src/sys/net/if_ethersubr.c:753
#22 0xc09977b2 in nfe_int_task (arg=0xc56ff000, pending=1)
    at /usr/src/sys/dev/nfe/if_nfe.c:2187
#23 0xc07387ca in taskqueue_run_locked (queue=0xc5702440)
    at /usr/src/sys/kern/subr_taskqueue.c:248
#24 0xc073895c in taskqueue_thread_loop (arg=0xc56ff130)
    at /usr/src/sys/kern/subr_taskqueue.c:385
#25 0xc06d1027 in fork_exit (callout=0xc07388a0 <taskqueue_thread_loop>,
    arg=0xc56ff130, frame=0xc538ed28) at /usr/src/sys/kern/kern_fork.c:861
#26 0xc09a5c24 in fork_trampoline () at
/usr/src/sys/i386/i386/exception.s:275
(kgdb)

-- 
-------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada   http://www.tancsa.com/