[syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_read_hdr (3)

[syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_read_hdr (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    5aca7966d2a7 Merge tag 'perf-tools-fixes-for-v6.17-2025-09..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12998c7c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1b093ccee5a9e08c
dashboard link: https://syzkaller.appspot.com/bug?extid=332bd4e9d148f11a87dc
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=14ccc534580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16998c7c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7dcf9f15bc6a/disk-5aca7966.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8836a30085d9/vmlinux-5aca7966.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b00f10dc0558/bzImage-5aca7966.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/78b7a2febda1/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+332bd4e9d148f11a87dc@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in ntfs_dir_emit fs/ntfs3/dir.c:335 [inline]
BUG: KMSAN: uninit-value in ntfs_read_hdr+0xfcc/0x13e0 fs/ntfs3/dir.c:385
 ntfs_dir_emit fs/ntfs3/dir.c:335 [inline]
 ntfs_read_hdr+0xfcc/0x13e0 fs/ntfs3/dir.c:385
 ntfs_readdir+0xf21/0x1a30 fs/ntfs3/dir.c:496
 iterate_dir+0x452/0x620 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:410 [inline]
 __se_sys_getdents64+0x17e/0x550 fs/readdir.c:396
 __x64_sys_getdents64+0x97/0xe0 fs/readdir.c:396
 x64_sys_call+0x3a14/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 ntfs_write_bh+0x6ae/0xe90 fs/ntfs3/fsntfs.c:1430
 indx_write fs/ntfs3/index.c:1027 [inline]
 indx_insert_into_buffer+0x287/0x2010 fs/ntfs3/index.c:1809
 indx_insert_entry+0xcde/0x1050 fs/ntfs3/index.c:1986
 ni_add_name+0xef7/0x11e0 fs/ntfs3/frecord.c:2995
 ntfs_link_inode+0x221/0x350 fs/ntfs3/inode.c:1728
 ntfs_link+0x20e/0x500 fs/ntfs3/namei.c:146
 vfs_link+0x8eb/0xb30 fs/namei.c:4854
 do_linkat+0x4af/0x1040 fs/namei.c:4924
 __do_sys_link fs/namei.c:4958 [inline]
 __se_sys_link fs/namei.c:4956 [inline]
 __x64_sys_link+0xd7/0x140 fs/namei.c:4956
 x64_sys_call+0x162f/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:87
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 hdr_insert_de+0x4c8/0x550 fs/ntfs3/index.c:838
 indx_insert_into_buffer+0x1b6/0x2010 fs/ntfs3/index.c:1805
 indx_insert_entry+0xcde/0x1050 fs/ntfs3/index.c:1986
 ni_add_name+0xef7/0x11e0 fs/ntfs3/frecord.c:2995
 ntfs_link_inode+0x221/0x350 fs/ntfs3/inode.c:1728
 ntfs_link+0x20e/0x500 fs/ntfs3/namei.c:146
 vfs_link+0x8eb/0xb30 fs/namei.c:4854
 do_linkat+0x4af/0x1040 fs/namei.c:4924
 __do_sys_link fs/namei.c:4958 [inline]
 __se_sys_link fs/namei.c:4956 [inline]
 __x64_sys_link+0xd7/0x140 fs/namei.c:4956
 x64_sys_call+0x162f/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:87
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4197 [inline]
 slab_alloc_node mm/slub.c:4240 [inline]
 kmem_cache_alloc_noprof+0x81b/0xec0 mm/slub.c:4247
 ntfs_link_inode+0x90/0x350 fs/ntfs3/inode.c:1716
 ntfs_link+0x20e/0x500 fs/ntfs3/namei.c:146
 vfs_link+0x8eb/0xb30 fs/namei.c:4854
 do_linkat+0x4af/0x1040 fs/namei.c:4924
 __do_sys_link fs/namei.c:4958 [inline]
 __se_sys_link fs/namei.c:4956 [inline]
 __x64_sys_link+0xd7/0x140 fs/namei.c:4956
 x64_sys_call+0x162f/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:87
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5963 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
=====================================================


---
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Forwarded: Re: [syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_read_hdr (3)

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***

Subject: Re: [syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_read_hdr (3)
Author: sidharthseela@gmail.com

Signed-off-by: Sidharth Seela <sidharthseela@gmail.com>
Reported-by: syzbot+332bd4e9d148f11a87dc@syzkaller.appspotmail.com

#syz test
diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index 1bf2a6593dec..3c44af1af9a0 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -718,7 +718,7 @@ static struct NTFS_DE *hdr_find_e(const struct ntfs_index *indx,
 				  const struct INDEX_HDR *hdr, const void *key,
 				  size_t key_len, const void *ctx, int *diff)
 {
-	struct NTFS_DE *e, *found = NULL;
+	struct NTFS_DE *e = NULL, *found = NULL;
 	NTFS_CMP_FUNC cmp = indx->cmp;
 	int min_idx = 0, mid_idx, max_idx = 0;
 	int diff2;
-- 
2.47.3

Forwarded: Re: [syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_read_hdr (3)

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***

Subject: Re: [syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_read_hdr (3)
Author: sidharthseela@gmail.com

Signed-off-by: Sidharth Seela <sidharthseela@gmail.com>
Reported-by: syzbot+332bd4e9d148f11a87dc@syzkaller.appspotmail.com

#syz test 
diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 37cbbee7fa58..6b14c13bda68 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -1716,6 +1716,7 @@ int ntfs_link_inode(struct inode *inode, struct dentry *dentry)
 	de = __getname();
 	if (!de)
 		return -ENOMEM;
+	memset(de,0,PATH_MAX);
 
 	/* Mark rw ntfs as dirty. It will be cleared at umount. */
 	ntfs_set_state(sbi, NTFS_DIRTY_DIRTY);
-- 
2.47.3

Forwarded:

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Subject: 
Author: kubik.bartlomiej@gmail.com

#syz test

Forwarded: Re: KMSAN: uninit-value in ntfs_read_hdr (3)

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Subject: Re: KMSAN: uninit-value in ntfs_read_hdr (3)
Author: kubik.bartlomiej@gmail.com

#syz test

Forwarded: Re: KMSAN: uninit-value in ntfs_read_hdr (3)

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Subject: Re: KMSAN: uninit-value in ntfs_read_hdr (3)
Author: kubik.bartlomiej@gmail.com

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
master