Another "impossible" mutex panic (Re: Panic in wait4())

On Tue, Mar 25, 2003 at 02:22:04PM -0800, Kris Kennaway wrote:
> I just got this on bento (running a kernel from Mar 17).  It was under
> heavy disk load at the time, which may or may not be relevant.
> 
> Kris
> 
> panic: mtx_lock() of spin mutex %s _at_ %s:%d
> panic messages:

I just got another one of these "impossible" panics on one of the
gohans (impossible because according to gdb the mutex is not a spin
mutex, so the assertion should not have fired).

panic: mtx_lock() of spin mutex %s _at_ %s:%d
panic messages:
---
Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x260
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc02bd3a8
stack pointer           = 0x10:0xd8fc1b48
frame pointer           = 0x10:0xd8fc1b48
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 78102 (sh)
Dumping 510 MB
ata0: resetting devices ..
done
 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 256 272 288 304 320 336 352 368 384 400 4\
16 432 448 464 480 496
---
#0  doadump () at /a/asami/portbuild/i386/src-client/sys/kern/kern_shutdown.c:239
239     /a/asami/portbuild/i386/src-client/sys/kern/kern_shutdown.c: No such file or directory.
        in /a/asami/portbuild/i386/src-client/sys/kern/kern_shutdown.c
(kgdb) bt
#0  doadump () at /a/asami/portbuild/i386/src-client/sys/kern/kern_shutdown.c:239
#1  0xc0165d15 in db_fncall (dummy1=1016, dummy2=0, dummy3=1016, dummy4=0xd8fc1934 "\f")
    at /a/asami/portbuild/i386/src-client/sys/ddb/db_command.c:546
#2  0xc0165a92 in db_command (last_cmdp=0xc0445260, cmd_table=0x0, aux_cmd_tablep=0xc043edd8,
    aux_cmd_tablep_end=0xc043eddc)
    at /a/asami/portbuild/i386/src-client/sys/ddb/db_command.c:346
#3  0xc0165ba6 in db_command_loop ()
    at /a/asami/portbuild/i386/src-client/sys/ddb/db_command.c:470
#4  0xc016892a in db_trap (type=12, code=0)
    at /a/asami/portbuild/i386/src-client/sys/ddb/db_trap.c:72
#5  0xc03c3d46 in kdb_trap (type=12, code=0, regs=0xd8fc1b08)
    at /a/asami/portbuild/i386/src-client/sys/i386/i386/db_interface.c:170
#6  0xc03d53d2 in trap_fatal (frame=0xd8fc1b08, eva=0)
    at /a/asami/portbuild/i386/src-client/sys/i386/i386/trap.c:838
#7  0xc03d50e2 in trap_pfault (frame=0xd8fc1b08, usermode=0, eva=608)
    at /a/asami/portbuild/i386/src-client/sys/i386/i386/trap.c:757
#8  0xc03d4c5d in trap (frame=
      {tf_fs = -654573544, tf_es = -1071185904, tf_ds = -1068957680, tf_edi = -987128304, tf_esi\
 = -1069422829, tf_ebp = -654566584, tf_isp = -654566604, tf_ebx = 608, tf_edx = 608, tf_ecx = 0\
, tf_eax = 608, tf_trapno = 12, tf_err = 0, tf_eip = -1070869592, tf_cs = 8, tf_eflags = 66118, \
tf_esp = -654566384, tf_ss = -1071153877})
    at /a/asami/portbuild/i386/src-client/sys/i386/i386/trap.c:444
#9  0xc03c56a8 in calltrap () at {standard input}:96
#10 0xc0277d2b in kvprintf (fmt=0xc041e713 " _at_ %s:%d", func=0xc02776d0 <snprintf_func>,
    arg=0xd8fc1c2c, radix=10, ap=0xd8fc1c74 "XXXbinarydataXXX")
    at /a/asami/portbuild/i386/src-client/sys/kern/subr_prf.c:668
#11 0xc027764e in vsnprintf (str=0xc0494840 "mtx_lock() of spin mutex ", size=0, format=0x0,
    ap=0x0) at /a/asami/portbuild/i386/src-client/sys/kern/subr_prf.c:413
#12 0xc025acec in panic (fmt=0xd8fc1c2c "YHI)
    at /a/asami/portbuild/i386/src-client/sys/kern/kern_shutdown.c:509
#13 0xc0251126 in _mtx_lock_flags (m=0xc045b5c0, opts=0,
    file=0xc041eef5 "/a/asami/portbuild/i386/src-client/sys/kern/kern_resource.c", line=940)
    at /a/asami/portbuild/i386/src-client/sys/kern/kern_mutex.c:332
#14 0xc0259a3d in uifree (uip=0xc045b5c0)
    at /a/asami/portbuild/i386/src-client/sys/kern/kern_resource.c:940
#15 0xc025650a in setreuid (td=0x0, uap=0x0)
    at /a/asami/portbuild/i386/src-client/sys/kern/kern_prot.c:902
#16 0xc03d56ee in syscall (frame=
      {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = 0, tf_esi = 0, tf_ebp = -1077941152, tf_isp \
=---Type <return> to continue, or q <return> to quit---
 -654566028, tf_ebx = 3, tf_edx = 0, tf_ecx = 0, tf_eax = 126, tf_trapno = 12, tf_err = 2, tf_ei\
p = 134699020, tf_cs = 31, tf_eflags = 659, tf_esp = -1077941228, tf_ss = 47})
    at /a/asami/portbuild/i386/src-client/sys/i386/i386/trap.c:1030
#17 0xc03c56fd in Xint0x80_syscall () at {standard input}:138
---Can't read userspace from dump, or kernel process---