panic: mutex process lock not owned at ../../../kern/sys_process.c:97

Hello,

On Wed, 30 Apr 2003, Radko Keves <rado_at_studnet.sk> got this panic. The panic
is easy to reproduce using `truss ls'. John Baldwin asked for a stack trace.
Here is one:

xp11# gdb -k /sys/i386/compile/XP11/kernel.debug vmcore.0
[...]
panic: mutex process lock not owned at ../../../kern/sys_process.c:97
panic: from debugger
[...]
#11 0xc01f1e5c in _mtx_assert (m=0xc28bc428, what=0, 
    file=0xc0384c1c "../../../kern/sys_process.c", line=97)
    at ../../../kern/kern_mutex.c:840
#12 0xc0221d11 in proc_read_regs (td=0xc28bc428, regs=0x0)
    at ../../../kern/sys_process.c:97
#13 0xc01be9f4 in procfs_doprocregs (td=0x0, p=0x61, pn=0xc2648f00, sb=0x0, 
    uio=0xce62bc7c) at ../../../fs/procfs/procfs_regs.c:84
#14 0xc01c10a5 in pfs_read (va=0x0)
    at ../../../fs/pseudofs/pseudofs_vnops.c:505
#15 0xc0259442 in vn_read (fp=0xc26db654, uio=0xce62bc7c, 
    active_cred=0xc28a5080, flags=0, td=0xc27ba130) at vnode_if.h:383
#16 0xc021cf42 in dofileread (td=0xc27ba130, fp=0xc26db654, fd=0, 
    buf=0xbfbffa90, nbyte=0, offset=0, flags=0) at file.h:227
#17 0xc021cdab in read (td=0xc27ba130, uap=0xce62bd10)
    at ../../../kern/sys_generic.c:106
#18 0xc035050e in syscall (frame=
      {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = -1077937444, tf_esi = 134570616, tf_ebp = -1077937384, tf_isp = -832389772, tf_ebx = -1077937440, tf_edx = 0, tf_ecx = 0, tf_eax = 3, tf_trapno = 12, tf_err = 2, tf_eip = 671885107, tf_cs = 31, tf_eflags = 534, tf_esp = -1077937556, tf_ss = 47})
    at ../../../i386/i386/trap.c:1021
#19 0xc034041d in Xint0x80_syscall () at {standard input}:138
---Can't read userspace from dump, or kernel process---

(kgdb) up 13
#13 0xc01be9f4 in procfs_doprocregs (td=0x0, p=0x61, pn=0xc2648f00, sb=0x0, 
    uio=0xce62bc7c) at ../../../fs/procfs/procfs_regs.c:84
84                      error = proc_read_regs(FIRST_THREAD_IN_PROC(p), &r);
(kgdb) list
79              PROC_UNLOCK(p);
80              if (kl < 0)
81                      error = EINVAL;
82              else
83                      /* XXXKSE: */
84                      error = proc_read_regs(FIRST_THREAD_IN_PROC(p), &r);
85              if (error == 0)
86                      error = uiomove(kv, kl, uio);
87              PROC_LOCK(p);
88              if (error == 0 && uio->uio_rw == UIO_WRITE) {
(kgdb) 

------                                                            ------ 
Philippe Charnier          charnier_at_{xp11.frmug.org,free.fr,FreeBSD.org}

    ``a PC not running FreeBSD is like a venusian with no tentacles'' 
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