[syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_iomap_begin (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 962528fef902 Merge tag 'gpio-fixes-for-v7.2-rc1' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b6af41580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f9f817cd15d2732a
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4ec878e25fafefa70f
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7d3cfc78dc93/disk-962528fe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/17f3cac25390/vmlinux-962528fe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/80baf6bfce4e/bzImage-962528fe.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b4ec8...@syzkaller.appspotmail.com

loop1: detected capacity change from 0 to 4096
=====================================================
BUG: KMSAN: uninit-value in ntfs_iomap_begin+0x8a3/0x1550 fs/ntfs3/inode.c:781
ntfs_iomap_begin+0x8a3/0x1550 fs/ntfs3/inode.c:781
iomap_iter+0x9d9/0x14f0 fs/iomap/iter.c:110
iomap_read_folio+0x67c/0xb20 fs/iomap/buffered-io.c:645
ntfs_read_folio+0x74f/0x770 fs/ntfs3/inode.c:652
filemap_read_folio mm/filemap.c:2510 [inline]
do_read_cache_folio+0x96d/0x13d0 mm/filemap.c:4140
do_read_cache_page mm/filemap.c:4206 [inline]
read_cache_page+0x63/0x1e0 mm/filemap.c:4215
read_mapping_page include/linux/pagemap.h:1009 [inline]
inode_read_data+0xbb/0x560 fs/ntfs3/inode.c:1058
ntfs_fill_super+0x720c/0x8820 fs/ntfs3/super.c:1582
get_tree_bdev_flags+0x6ef/0x930 fs/super.c:1634
get_tree_bdev+0x38/0x50 fs/super.c:1657
ntfs_fs_get_tree+0x35/0x40 fs/ntfs3/super.c:1819
vfs_get_tree+0xae/0x5d0 fs/super.c:1694
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3765 [inline]
do_new_mount+0x885/0x1dc0 fs/namespace.c:3841
path_mount+0x7a2/0x20a0 fs/namespace.c:4161
do_mount fs/namespace.c:4174 [inline]
__do_sys_mount fs/namespace.c:4390 [inline]
__se_sys_mount+0x704/0x7f0 fs/namespace.c:4367
__x64_sys_mount+0xed/0x180 fs/namespace.c:4367
x64_sys_call+0x39f0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:166
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15d/0x3c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable lcn created at:
ntfs_iomap_begin+0x157/0x1550 fs/ntfs3/inode.c:742
iomap_iter+0x9d9/0x14f0 fs/iomap/iter.c:110

CPU: 0 UID: 0 PID: 5852 Comm: syz.1.9 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
=====================================================


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