panic in knote

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello
in my daily tests of HEAD:
https://www-soc.lip6.fr/~bouyer/NetBSD-tests/xen/HEAD/
I've seen twice this panic:

kernel/kqueue/t_proc4 (80/939): 1 test cases
    proc4: [ 538.1439841] uvm_fault(0xc287759c, 0, 2) -> 0xe
[ 538.1642020] fatal page fault in supervisor mode
[ 538.1755046] trap type 6 code 0x2 eip 0xc0d657ac cs 0x8 eflags 0x10286 cr2 0x54 ilevel 0 esp 0xda7b8e78
[ 538.1985618] curlwp 0xc4d70900 pid 23901 lid 23901 lowest kstack 0xda7b62c0
[ 538.2145388] panic: trap
[ 538.2145388] cpu0: Begin traceback...
[ 538.2294995] vpanic(c12d339c,da7b8d18,da7b8dd4,c01306b2,c12d339c,da7b8de0,da7b8de0,5d5d,da7b62c0,10286) at netbsd:vpanic+0x196
[ 538.2537154] panic(c12d339c,da7b8de0,da7b8de0,5d5d,da7b62c0,10286,54,0,da7b8e78,c287759c) at netbsd:panic+0x18
[ 538.2847793] trap() at netbsd:trap+0xd7c
[ 538.2949956] --- trap (number 6) ---
[ 538.3051892] mutex_init(54,2,0,da7b8e60,c04bdd42,c4c391c0,c4c391c0,c4c391c0,54,c4c391c0) at netbsd:mutex_init+0x9
[ 538.3336643] knote_proc_fork_track(c4c23c48,c4a6b040,0,da7b8ea4,c0d0f8d8,c36b4440,c36b4440,c4a6b040,c4d70900,da7b8f10) at netbsd:knote_proc_fork_track+0xce
[ 538.3636624] knote_proc_fork(c4a6b040,c36b4440,da711000,0,0,0,c0d549e0,c4c391c0,da7b8ef4,0) at netbsd:knote_proc_fork+0x97
[ 538.3945229] fork1(c4d70900,0,14,0,0,c0d549e0,0,da7b8f60,da7b8f9c,c04bd5ab) at netbsd:fork1+0x667
[ 538.4238665] sys_fork(c4d70900,da7b8f68,da7b8f60,c23454c8,1,2,da7b8f60,da7b8f68,0,0) at netbsd:sys_fork+0x48
[ 538.4556545] syscall() at netbsd:syscall+0x17c
[ 538.4648600] --- syscall (number 2) ---
[ 538.4822324] bb3b7027:
[ 538.4876585] cpu0: End traceback...

any idea ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--