syzbot


UBSAN: shift-out-of-bounds in dbJoin (2)

Status: upstream: reported C repro on 2025/12/06 16:31
Subsystems: jfs
[Documentation on labels]
Reported-by: syzbot+fa603ae6b02658401ca7@syzkaller.appspotmail.com
First crash: 4d22h, last: 4d14h
Cause bisection: failed (error log, bisect log)
  
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] jfs: Add a sanity check for budmin 1 (1) 2025/12/07 03:52
[syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbJoin (2) 1 (3) 2025/12/07 03:52
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream UBSAN: shift-out-of-bounds in dbJoin jfs -1 C error 3 769d 1154d 25/29 fixed on 2024/01/30 15:47
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/12/07 03:18 25m eadavis@qq.com patch upstream OK log

Sample crash report:
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:2795:11
shift exponent 132 is too large for 32-bit type 'int'
CPU: 0 UID: 0 PID: 123 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
 __ubsan_handle_shift_out_of_bounds+0x386/0x410 lib/ubsan.c:494
 dbJoin+0x2dc/0x300 fs/jfs/jfs_dmap.c:2795
 dbFreeBits+0x4e1/0xdb0 fs/jfs/jfs_dmap.c:2340
 dbFreeDmap fs/jfs/jfs_dmap.c:2089 [inline]
 dbFree+0x336/0x650 fs/jfs/jfs_dmap.c:398
 txFreeMap+0x7ff/0xde0 fs/jfs/jfs_txnmgr.c:2535
 txUpdateMap+0x308/0x9c0 fs/jfs/jfs_txnmgr.c:-1
 txLazyCommit fs/jfs/jfs_txnmgr.c:2665 [inline]
 jfs_lazycommit+0x3f1/0xa10 fs/jfs/jfs_txnmgr.c:2734
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x52d/0xa60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
---[ end trace ]---
Kernel panic - not syncing: UBSAN: panic_on_warn set ...
CPU: 0 UID: 0 PID: 123 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x99/0x250 lib/dump_stack.c:120
 vpanic+0x237/0x6d0 kernel/panic.c:489
 panic+0xb9/0xc0 kernel/panic.c:626
 check_panic_on_warn+0x89/0xb0 kernel/panic.c:376
 __ubsan_handle_shift_out_of_bounds+0x386/0x410 lib/ubsan.c:494
 dbJoin+0x2dc/0x300 fs/jfs/jfs_dmap.c:2795
 dbFreeBits+0x4e1/0xdb0 fs/jfs/jfs_dmap.c:2340
 dbFreeDmap fs/jfs/jfs_dmap.c:2089 [inline]
 dbFree+0x336/0x650 fs/jfs/jfs_dmap.c:398
 txFreeMap+0x7ff/0xde0 fs/jfs/jfs_txnmgr.c:2535
 txUpdateMap+0x308/0x9c0 fs/jfs/jfs_txnmgr.c:-1
 txLazyCommit fs/jfs/jfs_txnmgr.c:2665 [inline]
 jfs_lazycommit+0x3f1/0xa10 fs/jfs/jfs_txnmgr.c:2734
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x52d/0xa60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Kernel Offset: disabled

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/03 00:28 upstream 4a26e7032d7d d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs UBSAN: shift-out-of-bounds in dbJoin
2025/12/02 23:17 upstream 4a26e7032d7d d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs UBSAN: shift-out-of-bounds in dbJoin
2025/12/02 20:02 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 05c93f3395ed d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-gce-arm64 UBSAN: shift-out-of-bounds in dbJoin
2025/12/02 18:07 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 05c93f3395ed d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-gce-arm64 UBSAN: shift-out-of-bounds in dbJoin
2025/12/02 17:18 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 05c93f3395ed d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-gce-arm64 UBSAN: shift-out-of-bounds in dbJoin
2025/12/02 16:27 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 05c93f3395ed d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 UBSAN: shift-out-of-bounds in dbJoin
* Struck through repros no longer work on HEAD.