Page fault in kern/kern_sig.c:1582

With GENERIC HEAD from Jan 11 09:07 UTC and syscall() stress
testing I got this page fault:

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0xcf75bc78
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xc0614dbb
stack pointer           = 0x10:0xcf301cbc
frame pointer           = 0x10:0xcf301cd0
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = resume, IOPL = 0
current process         = 35328 (syscall)
[thread pid 35328 tid 100197 ]
Stopped at      psignal+0x97:   testl   %eax,0(%esi,%edx,4)
db> where
Tracing pid 35328 tid 100197 td 0xc1c87a10
psignal(c1e283f0,1,0,c1c87a10,c1ece9d8) at psignal+0x97
kill(c1c87a10,cf301d14,2,0,292) at kill+0xd8
syscall(2f,2f,2f,2804f6c0,bfbfeaa4) at syscall+0x128

(kgdb) l *0xc0614dbb
0xc0614dbb is in psignal (../../../kern/kern_sig.c:1582).
1577     * way to deliver signal.
1578     */
1579    signal_td = NULL;
1580    mtx_lock_spin(&sched_lock);
1581    FOREACH_THREAD_IN_PROC(p, td) {
1582            if (td->td_waitset != NULL &&
1583                SIGISMEMBER(*(td->td_waitset), sig)) {
1584                            mtx_unlock_spin(&sched_lock);
1585                            return (td);
1586            }

More info at http://www.holm.cc/stress/log/cons106.html
-- 
Peter Holm