[syzbot] [hfs?] KMSAN: uninit-value in hfsplus_strcasecmp (2)

[syzbot <syzbot+d80abb5b890d39261e72@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    603c05a1639f Merge tag 'nfs-for-6.19-2' of git://git.linux..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=178b339a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=46b5f80a6e7aaa5c
dashboard link: https://syzkaller.appspot.com/bug?extid=d80abb5b890d39261e72
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=157be39a580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12625a3a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f5064e5f9c76/disk-603c05a1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c466bcf334e3/vmlinux-603c05a1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4e1318b36fb1/bzImage-603c05a1.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a0364f040b52/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d80abb5b890d39261e72@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 1024
=====================================================
BUG: KMSAN: uninit-value in case_fold fs/hfsplus/unicode.c:26 [inline]
BUG: KMSAN: uninit-value in hfsplus_strcasecmp+0x63a/0x980 fs/hfsplus/unicode.c:67
 case_fold fs/hfsplus/unicode.c:26 [inline]
 hfsplus_strcasecmp+0x63a/0x980 fs/hfsplus/unicode.c:67
 hfsplus_cat_case_cmp_key+0xb9/0x190 fs/hfsplus/catalog.c:26
 hfs_find_rec_by_key+0xae/0x240 fs/hfsplus/bfind.c:89
 __hfsplus_brec_find+0x274/0x840 fs/hfsplus/bfind.c:124
 hfsplus_brec_find+0x4ec/0xa10 fs/hfsplus/bfind.c:190
 hfsplus_find_cat+0x3b0/0x4f0 fs/hfsplus/catalog.c:220
 hfsplus_iget+0x815/0xc30 fs/hfsplus/super.c:96
 hfsplus_fill_super+0x1550/0x2580 fs/hfsplus/super.c:548
 get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1691
 get_tree_bdev+0x38/0x50 fs/super.c:1714
 hfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:680
 vfs_get_tree+0xb3/0x5c0 fs/super.c:1751
 fc_mount fs/namespace.c:1199 [inline]
 do_new_mount_fc fs/namespace.c:3636 [inline]
 do_new_mount+0x879/0x1700 fs/namespace.c:3712
 path_mount+0x749/0x1fb0 fs/namespace.c:4022
 do_mount fs/namespace.c:4035 [inline]
 __do_sys_mount fs/namespace.c:4224 [inline]
 __se_sys_mount+0x6f7/0x7e0 fs/namespace.c:4201
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4201
 x64_sys_call+0x38cb/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 hfsplus_cat_build_key_uni fs/hfsplus/catalog.c:77 [inline]
 hfsplus_find_cat+0x356/0x4f0 fs/hfsplus/catalog.c:217
 hfsplus_iget+0x815/0xc30 fs/hfsplus/super.c:96
 hfsplus_fill_super+0x1550/0x2580 fs/hfsplus/super.c:548
 get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1691
 get_tree_bdev+0x38/0x50 fs/super.c:1714
 hfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:680
 vfs_get_tree+0xb3/0x5c0 fs/super.c:1751
 fc_mount fs/namespace.c:1199 [inline]
 do_new_mount_fc fs/namespace.c:3636 [inline]
 do_new_mount+0x879/0x1700 fs/namespace.c:3712
 path_mount+0x749/0x1fb0 fs/namespace.c:4022
 do_mount fs/namespace.c:4035 [inline]
 __do_sys_mount fs/namespace.c:4224 [inline]
 __se_sys_mount+0x6f7/0x7e0 fs/namespace.c:4201
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4201
 x64_sys_call+0x38cb/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable tmp created at:
 hfsplus_find_cat+0x43/0x4f0 fs/hfsplus/catalog.c:197
 hfsplus_iget+0x815/0xc30 fs/hfsplus/super.c:96

CPU: 1 UID: 0 PID: 6037 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
=====================================================


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