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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fbafc3e621c3 Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=17192f76e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=50d8672fea106e5387bb
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=16b0a595e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=140e23c9e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1520f7b6daa4/disk-fbafc3e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8b490af009d5/vmlinux-fbafc3e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/202ca200f4a4/bzImage-fbafc3e6.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/0fd11f6357c0/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+50d867...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 1024
=====================================================
BUG: KMSAN: uninit-value in hfsplus_cat_case_cmp_key+0xf1/0x190 fs/hfsplus/catalog.c:23
hfsplus_cat_case_cmp_key+0xf1/0x190 fs/hfsplus/catalog.c:23
hfs_find_rec_by_key+0xb0/0x240 fs/hfsplus/bfind.c:100
__hfsplus_brec_find+0x26b/0x7b0 fs/hfsplus/bfind.c:135
hfsplus_brec_find+0x445/0x970 fs/hfsplus/bfind.c:195
hfsplus_brec_read+0x46/0x1a0 fs/hfsplus/bfind.c:222
hfsplus_find_cat+0xdb/0x460 fs/hfsplus/catalog.c:202
hfsplus_iget+0x740/0xaf0 fs/hfsplus/super.c:82
hfsplus_fill_super+0x151b/0x26f0 fs/hfsplus/super.c:503
mount_bdev+0x3d7/0x560 fs/super.c:1650
hfsplus_mount+0x4d/0x60 fs/hfsplus/super.c:641
legacy_get_tree+0x110/0x290 fs/fs_context.c:662
vfs_get_tree+0xa5/0x520 fs/super.c:1771
do_new_mount+0x68d/0x1550 fs/namespace.c:3337
path_mount+0x73d/0x1f20 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3863
__x64_sys_mount+0xe4/0x140 fs/namespace.c:3863
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
slab_alloc_node mm/slub.c:3478 [inline]
__kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc+0x121/0x3c0 mm/slab_common.c:1020
kmalloc include/linux/slab.h:604 [inline]
hfsplus_find_init+0x91/0x250 fs/hfsplus/bfind.c:21
hfsplus_iget+0x3e1/0xaf0 fs/hfsplus/super.c:80
hfsplus_fill_super+0x151b/0x26f0 fs/hfsplus/super.c:503
mount_bdev+0x3d7/0x560 fs/super.c:1650
hfsplus_mount+0x4d/0x60 fs/hfsplus/super.c:641
legacy_get_tree+0x110/0x290 fs/fs_context.c:662
vfs_get_tree+0xa5/0x520 fs/super.c:1771
do_new_mount+0x68d/0x1550 fs/namespace.c:3337
path_mount+0x73d/0x1f20 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3863
__x64_sys_mount+0xe4/0x140 fs/namespace.c:3863
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 4989 Comm: syz-executor165 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


---
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 syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
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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.

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(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

[Lizhi Xu]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fbafc3e621c3

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 1986b4f18a90..33eb7e5a08b3 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -57,7 +57,7 @@ static int hfsplus_system_read_inode(struct inode *inode)

struct inode *hfsplus_iget(struct super_block *sb, unsigned long ino)
{
- struct hfs_find_data fd;
+ struct hfs_find_data fd = {};
struct inode *inode;
int err;

[syzbot]

Hello,

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

loop0: detected capacity change from 0 to 1024
=====================================================
BUG: KMSAN: uninit-value in hfsplus_cat_case_cmp_key+0xf1/0x190 fs/hfsplus/catalog.c:23
hfsplus_cat_case_cmp_key+0xf1/0x190 fs/hfsplus/catalog.c:23
hfs_find_rec_by_key+0xb0/0x240 fs/hfsplus/bfind.c:100
__hfsplus_brec_find+0x26b/0x7b0 fs/hfsplus/bfind.c:135
hfsplus_brec_find+0x445/0x970 fs/hfsplus/bfind.c:195
hfsplus_brec_read+0x46/0x1a0 fs/hfsplus/bfind.c:222
hfsplus_find_cat+0xdb/0x460 fs/hfsplus/catalog.c:202

hfsplus_iget+0x752/0xb00 fs/hfsplus/super.c:82

hfsplus_fill_super+0x151b/0x26f0 fs/hfsplus/super.c:503
mount_bdev+0x3d7/0x560 fs/super.c:1650
hfsplus_mount+0x4d/0x60 fs/hfsplus/super.c:641
legacy_get_tree+0x110/0x290 fs/fs_context.c:662
vfs_get_tree+0xa5/0x520 fs/super.c:1771
do_new_mount+0x68d/0x1550 fs/namespace.c:3337
path_mount+0x73d/0x1f20 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3863
__x64_sys_mount+0xe4/0x140 fs/namespace.c:3863
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
slab_alloc_node mm/slub.c:3478 [inline]
__kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc+0x121/0x3c0 mm/slab_common.c:1020
kmalloc include/linux/slab.h:604 [inline]
hfsplus_find_init+0x91/0x250 fs/hfsplus/bfind.c:21

hfsplus_iget+0x3f3/0xb00 fs/hfsplus/super.c:80

hfsplus_fill_super+0x151b/0x26f0 fs/hfsplus/super.c:503
mount_bdev+0x3d7/0x560 fs/super.c:1650
hfsplus_mount+0x4d/0x60 fs/hfsplus/super.c:641
legacy_get_tree+0x110/0x290 fs/fs_context.c:662
vfs_get_tree+0xa5/0x520 fs/super.c:1771
do_new_mount+0x68d/0x1550 fs/namespace.c:3337
path_mount+0x73d/0x1f20 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3863
__x64_sys_mount+0xe4/0x140 fs/namespace.c:3863
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 5485 Comm: syz-executor.0 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================

Tested on:

commit: fbafc3e6 Merge tag 'for_linus' of git://git.kernel.org..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16eca09ae80000

kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=50d8672fea106e5387bb
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=11e5c579e80000

[Lizhi Xu]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fbafc3e621c3

diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c
index ca2ba8c9f82e..6773f6d2508f 100644
--- a/fs/hfsplus/bfind.c
+++ b/fs/hfsplus/bfind.c
@@ -23,6 +23,7 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
return -ENOMEM;
fd->search_key = ptr;
fd->key = ptr + tree->max_key_len + 2;
+ fd->key->cat.parent = 0;
hfs_dbg(BNODE_REFS, "find_init: %d (%p)\n",
tree->cnid, __builtin_return_address(0));
switch (tree->cnid) {

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+50d867...@syzkaller.appspotmail.com

Tested on:

commit: fbafc3e6 Merge tag 'for_linus' of git://git.kernel.org..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

console output: https://syzkaller.appspot.com/x/log.txt?x=15b83d1ae80000

kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=50d8672fea106e5387bb
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=13c8a595e80000

Note: testing is done by a robot and is best-effort only.