panic: maddr rwlock 0x

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f9943f26ca81 Use an iterator in uvmpd_scan_active() to pre..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=1456169a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=575f21bd59bdbf8a7ce8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d6622753111d/disk-f9943f26.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/66335b49a51a/bsd-f9943f26.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a84aac66fddb/kernel-f9943f26.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+575f21...@syzkaller.appspotmail.com

panic: maddr rwlock 0x
ffff8000015a8860: ente
r read deadlock
Starting stack trace...
panic(ffffffff83353f60) at panic+0x1d0 sys/kern/subr_prf.c:229
rw_do_enter_read(ffff8000015a8860,0) at rw_do_enter_read+0x4d2 sys/kern/kern_rwlock.c:379
in6_hasmulti(fffffd806d9b9af0,ffff8000015a8800) at in6_hasmulti+0x41 in6_lookupmulti sys/netinet6/in6.c:-1 [inline]
in6_hasmulti(fffffd806d9b9af0,ffff8000015a8800) at in6_hasmulti+0x41 sys/netinet6/in6.c:1150
ip6_output(fffffd806d9b9a00,ffffffff839eee58,0,0,ffff80002a1fe9a0,0) at ip6_output+0x13bd sys/netinet6/ip6_output.c:507
mld6_sendpkt(ffff80000154ae00,83,0) at mld6_sendpkt+0x385 sys/netinet6/mld6.c:499
mld6_fasttimo() at mld6_fasttimo+0x16d mld6_checktimer sys/netinet6/mld6.c:395 [inline]
mld6_fasttimo() at mld6_fasttimo+0x16d sys/netinet6/mld6.c:369
pffasttimo(ffffffff83a15020) at pffasttimo+0x184 sys/kern/uipc_domain.c:-1
timeout_run(ffffffff83835dd8,ffffffff83a15020) at timeout_run+0x159 sys/kern/kern_timeout.c:698
softclock_thread_run(ffffffff83835dd8) at softclock_thread_run+0xe7 sys/kern/kern_timeout.c:842
softclock_thread_mp(ffff8000ffffe7c8) at softclock_thread_mp+0x86
end trace frame: 0x0, count: 247
End of stack trace.


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