uvm_fault: db_enter (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1eab3ea7ad62 Clean-up BUILDINFO from /home/_sysupgrade lik..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=127bf5f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=823760782418600844b6

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5732daa5f887/disk-1eab3ea7.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/c52dd82b8cba/bsd-1eab3ea7.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/733e7fcb6521/kernel-1eab3ea7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+823760...@syzkaller.appspotmail.com

uvm_fault(fffffd807eb8d8e8,820152df000,0,2) at uvm_fault+0x106 sys/uvm/uvm_fault.c:668
upageflttrap(ffff80003c5c9350,820152df000) at upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:188
usertrap(ffff80003c5c9350) at usertrap+0x2d8 sys/arch/amd64/amd64/trap.c:436
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x82090fef5f0, count: -16
ddb{0}> machine ddbcpu 1
Stopped at db_enter+0x25: addq $0x8,%rsp
ddb{1}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437
witness_checkorder(ffff800001557030,9,0) at witness_checkorder+0x1b4
rw_do_enter_write(ffff800001557018,0) at rw_do_enter_write+0xb7 sys/kern/kern_rwlock.c:233
unveil_delete_names(ffff800001557000) at unveil_delete_names+0x3d sys/kern/kern_unveil.c:102
unveil_destroy(ffff80002a422250) at unveil_destroy+0xbd sys/kern/kern_unveil.c:183
exit1(ffff80003c5af470,0,0,1) at exit1+0x60f sys/kern/kern_exit.c:233
sys_exit(ffff80003c5af470,ffff80002b7e0e60,ffff80002b7e0db0) at sys_exit+0x1a
syscall(ffff80002b7e0e60) at syscall+0xb08 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002b7e0e60) at syscall+0xb08 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7ec1fb80cbc0, count: -9


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