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

[syzbot <syzbot+3ae6be33a50b5aae4dab@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in hfs_revalidate_dentry

loop0: detected capacity change from 0 to 64
=====================================================
BUG: KMSAN: uninit-value in hfs_revalidate_dentry+0x30b/0x3f0 fs/hfs/sysdep.c:30
 hfs_revalidate_dentry+0x30b/0x3f0 fs/hfs/sysdep.c:30
 lookup_fast+0x418/0x8e0
 walk_component fs/namei.c:2000 [inline]
 link_path_walk+0x817/0x1490 fs/namei.c:2331
 path_lookupat+0xd9/0x6f0 fs/namei.c:2484
 filename_lookup+0x22f/0x750 fs/namei.c:2514
 user_path_at_empty+0x8b/0x3a0 fs/namei.c:2921
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3689 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x66b/0x810 fs/namespace.c:3875
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
 x64_sys_call+0x2bf4/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2175 [inline]
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0x2de/0x1400 mm/slub.c:2391
 ___slab_alloc+0x1184/0x33d0 mm/slub.c:3525
 __slab_alloc mm/slub.c:3610 [inline]
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmem_cache_alloc_lru+0x6d7/0xbe0 mm/slub.c:3864
 alloc_inode_sb include/linux/fs.h:3091 [inline]
 hfs_alloc_inode+0x5a/0xd0 fs/hfs/super.c:165
 alloc_inode+0x86/0x460 fs/inode.c:261
 iget_locked+0x2bf/0xee0 fs/inode.c:1280
 hfs_btree_open+0x16c/0x1aa0 fs/hfs/btree.c:38
 hfs_mdb_get+0x1fe2/0x28b0 fs/hfs/mdb.c:199
 hfs_fill_super+0x1cf6/0x23c0 fs/hfs/super.c:406
 mount_bdev+0x397/0x520 fs/super.c:1658
 hfs_mount+0x4d/0x60 fs/hfs/super.c:456
 legacy_get_tree+0x114/0x290 fs/fs_context.c:662
 vfs_get_tree+0xa7/0x570 fs/super.c:1779
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
 path_mount+0x742/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x725/0x810 fs/namespace.c:3875
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
 x64_sys_call+0x2bf4/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 PID: 5493 Comm: syz-executor.0 Not tainted 6.9.0-rc3-syzkaller-00355-g7efd0a74039f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
=====================================================


Tested on:

commit:         7efd0a74 Merge tag 'ata-6.9-rc4' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1602674d180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=807e31f7fd7666b5
dashboard link: https://syzkaller.appspot.com/bug?extid=3ae6be33a50b5aae4dab
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.