uvm_fault: pf_purge_expired_states

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 24f569d23f3e Use a per cpu pool cache for pmap_pv_pool
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=129af96ee80000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=c6456cb3efc1bdf970a5

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/956005c0f045/disk-24f569d2.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/405fb40edec7/bsd-24f569d2.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9928fa10620a/kernel-24f569d2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6456c...@syzkaller.appspotmail.com

uvm_fault(0xffffffff82d1e840, 0x444, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at pf_purge_expired_states+0x187: movl 0x444(%r14,%rbx,4),%r15d
TID PID UID PRFLAGS PFLAGS CPU COMMAND
*243657 87522 0 0x14000 0x200 0 systqmp
pf_purge_expired_states(40,40) at pf_purge_expired_states+0x187 pf_state_expires sys/net/pf.c:1704 [inline]
pf_purge_expired_states(40,40) at pf_purge_expired_states+0x187 sys/net/pf.c:1922
pf_purge_states(0) at pf_purge_states+0x3e sys/net/pf.c:1630
taskq_thread(ffffffff82b6e310) at taskq_thread+0xe5 sys/kern/kern_task.c:450
end trace frame: 0x0, count: 12
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