Syzbot reports uninitialized value access issue as below:

loop0: detected capacity change from 0 to 64 ===================================================== BUG: KMSAN: uninit-value in hfs_revalidate_dentry+0x307/0x3f0 fs/hfs/sysdep.c:30 hfs_revalidate_dentry+0x307/0x3f0 fs/hfs/sysdep.c:30 d_revalidate fs/namei.c:862 [inline] lookup_fast+0x89e/0x8e0 fs/namei.c:1649 walk_component fs/namei.c:2001 [inline] link_path_walk+0x817/0x1480 fs/namei.c:2332 path_lookupat+0xd9/0x6f0 fs/namei.c:2485 filename_lookup+0x22e/0x740 fs/namei.c:2515 user_path_at_empty+0x8b/0x390 fs/namei.c:2924 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+0xe4/0x140 fs/namespace.c:3875 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+0x63/0x6b

BUG: KMSAN: uninit-value in hfs_ext_read_extent fs/hfs/extent.c:196 [inline] BUG: KMSAN: uninit-value in hfs_get_block+0x92d/0x1620 fs/hfs/extent.c:366 hfs_ext_read_extent fs/hfs/extent.c:196 [inline] hfs_get_block+0x92d/0x1620 fs/hfs/extent.c:366 block_read_full_folio+0x4ff/0x11b0 fs/buffer.c:2271 hfs_read_folio+0x55/0x60 fs/hfs/inode.c:39 filemap_read_folio+0x148/0x4f0 mm/filemap.c:2426 do_read_cache_folio+0x7c8/0xd90 mm/filemap.c:3553 do_read_cache_page mm/filemap.c:3595 [inline] read_cache_page+0xfb/0x2f0 mm/filemap.c:3604 read_mapping_page include/linux/pagemap.h:755 [inline] hfs_btree_open+0x928/0x1ae0 fs/hfs/btree.c:78 hfs_mdb_get+0x260c/0x3000 fs/hfs/mdb.c:204 hfs_fill_super+0x1fb1/0x2790 fs/hfs/super.c:406 mount_bdev+0x628/0x920 fs/super.c:1359 hfs_mount+0xcd/0xe0 fs/hfs/super.c:456 legacy_get_tree+0x167/0x2e0 fs/fs_context.c:610 vfs_get_tree+0xdc/0x5d0 fs/super.c:1489 do_new_mount+0x7a9/0x16f0 fs/namespace.c:3145 path_mount+0xf98/0x26a0 fs/namespace.c:3475 do_mount fs/namespace.c:3488 [inline] __do_sys_mount fs/namespace.c:3697 [inline] __se_sys_mount+0x919/0x9e0 fs/namespace.c:3674 __ia32_sys_mount+0x15b/0x1b0 fs/namespace.c:3674 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178 do_fast_syscall_32+0x37/0x80 arch/x86/entry/common.c:203 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:246 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Uninit was created at: __alloc_pages+0x9a6/0xe00 mm/page_alloc.c:4590 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] alloc_slab_page mm/slub.c:2190 [inline] allocate_slab mm/slub.c:2354 [inline] new_slab+0x2d7/0x1400 mm/slub.c:2407 ___slab_alloc+0x16b5/0x3970 mm/slub.c:3540 __slab_alloc mm/slub.c:3625 [inline] __slab_alloc_node mm/slub.c:3678 [inline] slab_alloc_node mm/slub.c:3850 [inline] kmem_cache_alloc_lru+0x64d/0xb30 mm/slub.c:3879 alloc_inode_sb include/linux/fs.h:3018 [inline] hfs_alloc_inode+0x5a/0xc0 fs/hfs/super.c:165 alloc_inode+0x83/0x440 fs/inode.c:260 new_inode_pseudo fs/inode.c:1005 [inline] new_inode+0x38/0x4f0 fs/inode.c:1031 hfs_new_inode+0x61/0x1010 fs/hfs/inode.c:186 hfs_mkdir+0x54/0x250 fs/hfs/dir.c:228 vfs_mkdir+0x49a/0x700 fs/namei.c:4126 do_mkdirat+0x529/0x810 fs/namei.c:4149 __do_sys_mkdirat fs/namei.c:4164 [inline] __se_sys_mkdirat fs/namei.c:4162 [inline] __x64_sys_mkdirat+0xc8/0x120 fs/namei.c:4162 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+0x63/0x6b

It missed to initialize .tz_secondswest, .cached_start and .cached_blocks fields in struct hfs_inode_info after hfs_alloc_inode(), fix it.

Cc: stable@vger.kernel.org Reported-by: syzbot+3ae6be33a50b5aae4dab@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-fsdevel/0000000000005ad04005ee48897f@google.co... Signed-off-by: Chao Yu chao@kernel.org --- fs/hfs/inode.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c index 8c34798a0715..744e10b46904 100644 --- a/fs/hfs/inode.c +++ b/fs/hfs/inode.c @@ -200,6 +200,7 @@ struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t HFS_I(inode)->flags = 0; HFS_I(inode)->rsrc_inode = NULL; HFS_I(inode)->fs_blocks = 0; + HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60; if (S_ISDIR(mode)) { inode->i_size = 2; HFS_SB(sb)->folder_count++; @@ -275,6 +276,8 @@ void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext, for (count = 0, i = 0; i < 3; i++) count += be16_to_cpu(ext[i].count); HFS_I(inode)->first_blocks = count; + HFS_I(inode)->cached_start = 0; + HFS_I(inode)->cached_blocks = 0;

inode->i_size = HFS_I(inode)->phys_size = log_size; HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;