syzbot


panic: ffs_blkfree: bad size (6)

Status: upstream: reported on 2026/01/08 23:36
Reported-by: syzbot+354f9e7b763606ac8c86@syzkaller.appspotmail.com
First crash: 4d20h, last: 4d20h
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
openbsd panic: ffs_blkfree: bad size (3) 2 1 731d 731d 0/3 auto-obsoleted due to no activity on 2024/04/11 20:56
openbsd panic: ffs_blkfree: bad size (5) 2 8 311d 339d 0/3 auto-obsoleted due to no activity on 2025/06/06 15:13
openbsd panic: ffs_blkfree: bad size (4) 2 5 515d 613d 0/3 auto-obsoleted due to no activity on 2024/11/14 17:32
openbsd panic: ffs_blkfree: bad size 2 2 2386d 2390d 0/3 auto-closed as invalid on 2019/10/25 14:12
openbsd panic: ffs_blkfree: bad size (2) 2 1 837d 837d 0/3 auto-obsoleted due to no activity on 2023/12/28 07:11

Sample crash report:
panic: ffs_blkfree: bad size
Starting stack trace...
panic(ffffffff833cf22b) at panic+0x1d0 sys/kern/subr_prf.c:229
ffs_blkfree(fffffd8079ba4ab0,4,4000) at ffs_blkfree+0xd4c sys/ufs/ffs/ffs_alloc.c:1285
ffs_indirtrunc(fffffd8079ba4ab0,fffffffffffffff4,16db40,ffffffffffffffff,0,ffff80003c460c38) at ffs_indirtrunc+0x7ca sys/ufs/ffs/ffs_inode.c:-1
ffs_truncate(fffffd8079ba4ab0,0,0,ffffffffffffffff) at ffs_truncate+0x103f sys/ufs/ffs/ffs_inode.c:297
ufs_inactive(ffff80003c460d90) at ufs_inactive+0x202 sys/ufs/ufs/ufs_inode.c:84
VOP_INACTIVE(fffffd805bc42a20,ffff8000ffffd9f8) at VOP_INACTIVE+0x104 sys/kern/vfs_vops.c:498
vrele(fffffd805bc42a20) at vrele+0x129 sys/kern/vfs_subr.c:837
ktrsettrace(ffff80002a265820,80001a2c,fffffd8071040e60,fffffd80097fd478) at ktrsettrace+0xe7 sys/kern/kern_ktrace.c:122
ktrops(ffff8000ffffd9f8,ffff80002a265820,0,80001a2c,fffffd8071040e60,fffffd80097fd478) at ktrops+0x26c sys/kern/kern_ktrace.c:573
doktrace(fffffd8071040e60,4,1a2c,0,ffff8000ffffd9f8) at doktrace+0x6bd ktrsetchildren sys/kern/kern_ktrace.c:595 [inline]
doktrace(fffffd8071040e60,4,1a2c,0,ffff8000ffffd9f8) at doktrace+0x6bd sys/kern/kern_ktrace.c:517
sys_ktrace(ffff8000ffffd9f8,ffff80003c461200,ffff80003c461150) at sys_ktrace+0x11c sys/kern/kern_ktrace.c:558
syscall(ffff80003c461200) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c461200) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xfcec122d750, count: 244
End of stack trace.

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/08 23:35 openbsd b9d9e3fc96bc c1f5c7d0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore panic: ffs_blkfree: bad size
* Struck through repros no longer work on HEAD.