netbsd-6 page fault in pmap_clear_attrs()

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

Hello,
anita runs on netbsd-6 occasionally fails with:
fatal page fault in supervisor mode

trap type 6 code 0 rip ffffffff802cb792 cs e030 rflags 10286 cr2  7fbfbff5bad8 
cpl 0 rsp ffffa0000d7b7790
panic: trap
cpu0: Begin traceback...
printf_nolog() at netbsd:printf_nolog
startlwp() at netbsd:startlwp
alltraps() at netbsd:alltraps+0xa7
pmap_clear_attrs() at netbsd:pmap_clear_attrs+0x70
genfs_do_putpages() at netbsd:genfs_do_putpages+0x42a
VOP_PUTPAGES() at netbsd:VOP_PUTPAGES+0x3a
uvm_map_clean() at netbsd:uvm_map_clean+0x176
sys___msync13() at netbsd:sys___msync13+0xbb
syscall() at netbsd:syscall+0xc4
cpu0: End traceback...

does it ring a bell to someone ?
Full report:
http://www-soc.lip6.fr/~bouyer/NetBSD-tests/xen/netbsd-6/amd64/201206070110Z_anita.txt

I've also seen faults in pmap_enter(), I guess it's the same problem.

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