[syzbot] [hfs?] KMSAN: uninit-value in hfs_bnode_dump

[syzbot] [hfs?] KMSAN: uninit-value in hfs_bnode_dump

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    1e1ba8d23dae Merge tag 'timers-clocksource-2025-03-26' of ..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1732e198580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=887673359f1a92bf
dashboard link: https://syzkaller.appspot.com/bug?extid=efd267470a41bc34bd98
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/97b3a10186d9/disk-1e1ba8d2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/de4a9446d205/vmlinux-1e1ba8d2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/529352453703/bzImage-1e1ba8d2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+efd267470a41bc34bd98@syzkaller.appspotmail.com

loop2: detected capacity change from 0 to 64
=====================================================
BUG: KMSAN: uninit-value in hfs_bnode_read_u8 fs/hfs/bnode.c:54 [inline]
BUG: KMSAN: uninit-value in hfs_bnode_dump+0x30e/0x4c0 fs/hfs/bnode.c:172
 hfs_bnode_read_u8 fs/hfs/bnode.c:54 [inline]
 hfs_bnode_dump+0x30e/0x4c0 fs/hfs/bnode.c:172
 hfs_brec_remove+0x868/0x9a0 fs/hfs/brec.c:225
 hfs_cat_move+0xfc9/0x12e0 fs/hfs/catalog.c:364
 hfs_rename+0x344/0x500 fs/hfs/dir.c:299
 vfs_rename+0x1d9d/0x2280 fs/namei.c:5086
 do_renameat2+0x1577/0x1b80 fs/namei.c:5235
 __do_sys_rename fs/namei.c:5282 [inline]
 __se_sys_rename fs/namei.c:5280 [inline]
 __x64_sys_rename+0xe8/0x140 fs/namei.c:5280
 x64_sys_call+0x3a1e/0x3c80 arch/x86/include/generated/asm/syscalls_64.h:83
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable data.i created at:
 hfs_bnode_read_u16 fs/hfs/bnode.c:-1 [inline]
 hfs_bnode_dump+0x3c5/0x4c0 fs/hfs/bnode.c:156
 hfs_brec_remove+0x868/0x9a0 fs/hfs/brec.c:225

CPU: 0 UID: 0 PID: 7333 Comm: syz.2.275 Not tainted 6.14.0-syzkaller-03576-g1e1ba8d23dae #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
=====================================================


---
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@googlegroups.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 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

Re: [syzbot] [hfs?] KMSAN: uninit-value in hfs_bnode_dump

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    8ffd015db85f Linux 6.15-rc2
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=105820cc580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e30b69a28cc940e1
dashboard link: https://syzkaller.appspot.com/bug?extid=efd267470a41bc34bd98
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=107c0470580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=158a6a3f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b099795f8c63/disk-8ffd015d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a10b15dc31a5/vmlinux-8ffd015d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/24a20f2e33c6/bzImage-8ffd015d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/c80aacb02924/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+efd267470a41bc34bd98@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in hfs_bnode_read_u8 fs/hfs/bnode.c:54 [inline]
BUG: KMSAN: uninit-value in hfs_bnode_dump+0x30e/0x4c0 fs/hfs/bnode.c:172
 hfs_bnode_read_u8 fs/hfs/bnode.c:54 [inline]
 hfs_bnode_dump+0x30e/0x4c0 fs/hfs/bnode.c:172
 hfs_brec_remove+0x868/0x9a0 fs/hfs/brec.c:225
 hfs_cat_move+0xfc9/0x12e0 fs/hfs/catalog.c:364
 hfs_rename+0x344/0x500 fs/hfs/dir.c:299
 vfs_rename+0x1d9d/0x2280 fs/namei.c:5086
 do_renameat2+0x1577/0x1b80 fs/namei.c:5235
 __do_sys_rename fs/namei.c:5282 [inline]
 __se_sys_rename fs/namei.c:5280 [inline]
 __x64_sys_rename+0xe8/0x140 fs/namei.c:5280
 x64_sys_call+0x3a1e/0x3c80 arch/x86/include/generated/asm/syscalls_64.h:83
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable data.i created at:
 hfs_bnode_read_u16 fs/hfs/bnode.c:-1 [inline]
 hfs_bnode_dump+0x3c5/0x4c0 fs/hfs/bnode.c:156
 hfs_brec_remove+0x868/0x9a0 fs/hfs/brec.c:225

CPU: 0 UID: 0 PID: 5792 Comm: syz-executor395 Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
=====================================================


---
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.