uvm_fault: done_flush

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8105fbd98be2 asn1t.h: whitespace tweaks
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=1643d522580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=4ee3ab1da53a97ca87ad

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/092612d65d64/disk-8105fbd9.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/bdadf547e092/bsd-8105fbd9.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/147bf5b5dd4a/kernel-8105fbd9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4ee3ab...@syzkaller.appspotmail.com

uvm_fault(fffffd806eabc3e0,95821d65000,0,2) at uvm_fault+0x106 sys/uvm/uvm_fault.c:627
upageflttrap(ffff80003c405d80,95821d65c18) at upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:192
usertrap(ffff80003c405d80) at usertrap+0x42f sys/arch/amd64/amd64/trap.c:632
recall_trap() at recall_trap+0x8
end trace frame: 0x0, count: -14
ddb{0}> machine ddbcpu 1
Stopped at done_flush+0x38: movl %eax,%dr6
ddb{1}> trace
end trace frame: 0x0, count: -1


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