linux-kernel - Forwarded: Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbSplit (3)

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Message-ID: <68d9938e.a70a0220.10c4b.0026.GAE@google.com>
Date: Sun, 28 Sep 2025 12:59:10 -0700
From: syzbot <syzbot+4c1966e88c28fa96e053@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Forwarded: Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbSplit (3)

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***

Subject: Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbSplit (3)
Author: xandfury@...il.com

syzbot <syzbot+4c1966e88c28fa96e053@...kaller.appspotmail.com> writes:

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    f1a3944c860b Merge tag ’bpf-fixes’ of git://git.kernel.org..
> git tree:       upstream
> console output: <https://syzkaller.appspot.com/x/log.txt?x=10d550d4580000>
> kernel config:  <https://syzkaller.appspot.com/x/.config?x=90837c100b88a636>
> dashboard link: <https://syzkaller.appspot.com/bug?extid=4c1966e88c28fa96e053>
> compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2
> syz repro:      <https://syzkaller.appspot.com/x/repro.syz?x=1250a270580000>
> C reproducer:   <https://syzkaller.appspot.com/x/repro.c?x=14d550d4580000>
>
> Downloadable assets:
> disk image (non-bootable): <https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-f1a3944c.raw.xz>
> vmlinux: <https://storage.googleapis.com/syzbot-assets/fbe8c2bb0602/vmlinux-f1a3944c.xz>
> kernel image: <https://storage.googleapis.com/syzbot-assets/b4268e0ec733/bzImage-f1a3944c.xz>
> mounted in repro: <https://storage.googleapis.com/syzbot-assets/10b2c382300e/mount_0.gz>
>   fsck result: failed (log: <https://syzkaller.appspot.com/x/fsck.log?x=14f49d74580000>)
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+4c1966e88c28fa96e053@...kaller.appspotmail.com
>
> loop0: detected capacity change from 0 to 32768
> ————[ cut here ]————
> UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:2629:11
> shift exponent 110 is too large for 32-bit type ’int’
> CPU: 0 UID: 0 PID: 5303 Comm: syz-executor956 Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0 PREEMPT(full) 
> 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_lvl+0x189/0x250 lib/dump_stack.c:120
>  ubsan_epilogue+0xa/0x40 lib/ubsan.c:231
>  __ubsan_handle_shift_out_of_bounds+0x386/0x410 lib/ubsan.c:492
>  dbSplit+0x1f8/0x200 fs/jfs/jfs_dmap.c:2629
>  dbAdjCtl+0x34c/0xa20 fs/jfs/jfs_dmap.c:2521
>  dbAllocDmap fs/jfs/jfs_dmap.c:2032 [inline]
>  dbAllocNear+0x2ee/0x3d0 fs/jfs/jfs_dmap.c:1243
>  dbAlloc+0x933/0xba0 fs/jfs/jfs_dmap.c:828
>  ea_write+0x374/0xdd0 fs/jfs/xattr.c:232
>  ea_put fs/jfs/xattr.c:619 [inline]
>  __jfs_setxattr+0xa01/0x1120 fs/jfs/xattr.c:792
>  __jfs_xattr_set+0xda/0x170 fs/jfs/xattr.c:941
>  __vfs_setxattr+0x439/0x480 fs/xattr.c:200
>  __vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
>  vfs_setxattr+0x16b/0x2f0 fs/xattr.c:321
>  do_setxattr fs/xattr.c:636 [inline]
>  filename_setxattr+0x274/0x600 fs/xattr.c:665
>  path_setxattrat+0x364/0x3a0 fs/xattr.c:713
>  __do_sys_lsetxattr fs/xattr.c:754 [inline]
>  __se_sys_lsetxattr fs/xattr.c:750 [inline]
>  __x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fdaa19996b9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 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:00007fffe3d43d28 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
> RAX: ffffffffffffffda RBX: 0000200000000200 RCX: 00007fdaa19996b9
> RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000200000000040
> RBP: 00002000000000c0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000040
> R13: 0031656c69662f2e R14: 0000000000000001 R15: 0000000000000001
>  </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