linux-kernel - Forwarded: Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbFindBits (2)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <68d888b0.050a0220.25d7ab.0431.GAE@google.com>
Date: Sat, 27 Sep 2025 18:00:32 -0700
From: syzbot <syzbot+9e90a1c5eedb9dc4c6cc@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Forwarded: Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in
 dbFindBits (2)

For archival purposes, forwarding an incoming command email to
linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com.

***

Subject: Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbFindBits (2)
Author: xandfury@...il.com

syzbot <syzbot+9e90a1c5eedb9dc4c6cc@...kaller.appspotmail.com> writes:

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    c2ee9f594da8 KVM: selftests: Fix build on on non-x86 archi..
> git tree:       upstream
> console output: <https://syzkaller.appspot.com/x/log.txt?x=134fc640580000>
> kernel config:  <https://syzkaller.appspot.com/x/.config?x=fc6f8ce8c5369043>
> dashboard link: <https://syzkaller.appspot.com/bug?extid=9e90a1c5eedb9dc4c6cc>
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      <https://syzkaller.appspot.com/x/repro.syz?x=118f0287980000>
> C reproducer:   <https://syzkaller.appspot.com/x/repro.c?x=128f8a5f980000>
>
> Downloadable assets:
> disk image (non-bootable): <https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-c2ee9f59.raw.xz>
> vmlinux: <https://storage.googleapis.com/syzbot-assets/8a3541902b13/vmlinux-c2ee9f59.xz>
> kernel image: <https://storage.googleapis.com/syzbot-assets/a00efacc2604/bzImage-c2ee9f59.xz>
> mounted in repro: <https://storage.googleapis.com/syzbot-assets/0a96c5cc2569/mount_0.gz>
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+9e90a1c5eedb9dc4c6cc@...kaller.appspotmail.com
>
> ERROR: (device loop0): remounting filesystem as read-only
> ERROR: (device loop0): dbDiscardAG: -EIO
> ERROR: (device loop0): dbAllocBits: leaf page corrupt
> ————[ cut here ]————
> UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:3028:55
> shift exponent 32 is too large for 32-bit type ’u32’ (aka ’unsigned int’)
> CPU: 0 UID: 0 PID: 5092 Comm: syz-executor128 Not tainted 6.12.0-rc4-syzkaller-00047-gc2ee9f594da8 #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:94 [inline]
>  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>  ubsan_epilogue lib/ubsan.c:231 [inline]
>  __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468
>  dbFindBits+0x11a/0x1d0 fs/jfs/jfs_dmap.c:3028
>  dbAllocDmapLev+0x1e9/0x4a0 fs/jfs/jfs_dmap.c:1985
>  dbAllocCtl+0x113/0x920 fs/jfs/jfs_dmap.c:1825
>  dbAllocAG+0x28f/0x10b0 fs/jfs/jfs_dmap.c:1364
>  dbDiscardAG+0x352/0xa20 fs/jfs/jfs_dmap.c:1613
>  jfs_ioc_trim+0x45a/0x6b0 fs/jfs/jfs_discard.c:105
>  jfs_ioctl+0x2cd/0x3e0 fs/jfs/ioctl.c:131
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:907 [inline]
>  __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f54e7034c99
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 90 48 89 f8 48 89
> f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
> f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffd37b5c358 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f54e7034c99
> RDX: 00000000200000c0 RSI: 00000000c0185879 RDI: 0000000000000004
> RBP: 00007f54e70ad5f0 R08: 000055557b4874c0 R09: 000055557b4874c0
> R10: 000055557b4874c0 R11: 0000000000000246 R12: 00007ffd37b5c380
> R13: 00007ffd37b5c5a8 R14: 431bde82d7b634db R15: 00007f54e707d03b
>  </TASK>
> —[ end trace ]—
>
>
> —
> This report is generated by a bot. It may contain errors.
> See <https://goo.gl/tpsmEJ> for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
>
> syzbot will keep track of this issue. See:
> <https://goo.gl/tpsmEJ#status> for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report’s subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master