KASAN: invalid memory access in setdisklabel

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 47df478b2278 Merge remote-tracking branch 'origin/master' ..
git tree: https://github.com/blackgnezdo/openbsd-src.git syzbot-kasan
console output: https://syzkaller.appspot.com/x/log.txt?x=14517bb9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=85e25e37d09e1b88
dashboard link: https://syzkaller.appspot.com/bug?extid=4b34bf468172c62700f3

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6bcc34127967/disk-47df478b.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/cf2fb6caefcf/bsd-47df478b.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1d4f9eb7d1fb/kernel-47df478b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b34bf...@syzkaller.appspotmail.com

panic: Caught invalid memory access at ffff800001852c94 size 2 op 0
Starting stack trace...
panic(ffffffff84637d3e) at panic+0x25b sys/kern/subr_prf.c:229
__asan_load2_noabort(ffff800001852c94) at __asan_load2_noabort+0x107
setdisklabel(ffff800000127800,ffff800001852800,3) at setdisklabel+0x258 dkcksum sys/kern/subr_disk.c:133 [inline]
setdisklabel(ffff800000127800,ffff800001852800,3) at setdisklabel+0x258 sys/kern/subr_disk.c:885
sdioctl(d01,84946467,ffff800001852800,2,ffff800029913c98) at sdioctl+0x9a7 sys/scsi/sd.c:909
VOP_IOCTL(ffff8000018da1c8,84946467,ffff800001852800,2,ffff800000119548,ffff800029913c98) at VOP_IOCTL+0x131 sys/kern/vfs_vops.c:264
vn_ioctl(ffff800001cfba48,84946467,ffff800001852800,ffff800029913c98) at vn_ioctl+0x18c sys/kern/vfs_vnops.c:537
sys_ioctl(ffff800029913c98,ffff80002997fb00,ffff80002997fa60) at sys_ioctl+0x868 sys/kern/sys_generic.c:510
syscall(ffff80002997fb00) at syscall+0x1089 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002997fb00) at syscall+0x1089 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xcfd2452f160, count: 248
End of stack trace.
syncing disks...


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