panic: vrele: ref cnt

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8a9424f8c5c9 Display distinct errors for various problemat..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=15563f00980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=434b095a663ae07c0c09

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/78ac68fe4e5e/disk-8a9424f8.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/5b8dcd25220c/bsd-8a9424f8.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cd3d1a7c5c25/kernel-8a9424f8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+434b09...@syzkaller.appspotmail.com

panic: vrele: ref cnt
Starting stack trace...
panic(ffffffff8295b62b) at panic+0x16f sys/kern/subr_prf.c:229
vrele(fffffd80676caa30) at vrele+0x195 sys/kern/vfs_subr.c:813
fdfree(ffff800032f534b0) at fdfree+0x1e3 sys/kern/kern_descrip.c:1210
exit1(ffff800032f534b0,0,0,1) at exit1+0x38a sys/kern/kern_exit.c:199
sys_exit(ffff800032f534b0,ffff80002a24ce60,ffff80002a24cdb0) at sys_exit+0x1a sys/kern/kern_exit.c:89
syscall(ffff80002a24ce60) at syscall+0x854 mi_syscall sys/sys/syscall_mi.h:180 [inline]
syscall(ffff80002a24ce60) at syscall+0x854 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7e3b5c72a840, count: 250
End of stack trace.


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