uvm_fault: ffs_blkfree (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8928aa246822 Provide an example how to disambiguate mktime..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=147701ba580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1bc15e68cd2a49e5
dashboard link: https://syzkaller.appspot.com/bug?extid=49318ab8bd8b8b7f7ddc

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b47cf31cf03a/disk-8928aa24.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/4bef20a91bde/bsd-8928aa24.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f3c6a4db3832/kernel-8928aa24.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+49318a...@syzkaller.appspotmail.com

uvm_fault(0xffffffff83a0b5a0, 0xffff8000133e2004, 0, 1) -> d
kernel: page fault trap, code=0
Stopped at ffs_blkfree+0x254: movl 0x4(%r12),%r15d
TID PID UID PRFLAGS PFLAGS CPU COMMAND
*438685 82070 0 0x2 0 0 syz-executor
ffs_blkfree(fffffd8073689e00,2592a,800) at ffs_blkfree+0x254 ffs_cgread sys/ufs/ffs/ffs_alloc.c:856 [inline]
ffs_blkfree(fffffd8073689e00,2592a,800) at ffs_blkfree+0x254 sys/ufs/ffs/ffs_alloc.c:1272
ffs_truncate(fffffd8073689e00,0,0,ffffffffffffffff) at ffs_truncate+0x1390 sys/ufs/ffs/ffs_inode.c:325
ufs_inactive(ffff80002a83bc00) at ufs_inactive+0x1ff sys/ufs/ufs/ufs_inode.c:84
VOP_INACTIVE(fffffd806d397798,ffff80002a746538) at VOP_INACTIVE+0xfb sys/kern/vfs_vops.c:498
vput(fffffd806d397798) at vput+0xdc sys/kern/vfs_subr.c:789
VOP_REMOVE(fffffd806d3970d8,fffffd806d397798,ffff80002a83bd68) at VOP_REMOVE+0x199 sys/kern/vfs_vops.c:336
dounlinkat(ffff80002a746538,ffffff9c,7bc1d6e82900,0) at dounlinkat+0x1c4 sys/kern/vfs_syscalls.c:1923
syscall(ffff80002a83bed0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a83bed0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7bc1d6e82db0, count: 6
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports. Insufficient info makes it difficult to find and fix bugs.


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