[syzbot] [ntfs3?] INFO: trying to register non-static key in ntfs_set_size

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 590b221ed425 Add linux-next specific files for 20250912
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1379b934580000
kernel config: https://syzkaller.appspot.com/x/.config?x=12a1d1f3a8199632
dashboard link: https://syzkaller.appspot.com/bug?extid=bdeb22a4b9a09ab9aa45
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=144aa762580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117c8762580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/63a963fc26db/disk-590b221e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0c2013d30830/vmlinux-590b221e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7ee4d3a8e8f6/bzImage-590b221e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/0f2061b3352a/mount_0.gz

The issue was bisected to:

commit 4e8011ffec79717e5fdac43a7e79faf811a384b7
Author: Tetsuo Handa <penguin...@I-love.SAKURA.ne.jp>
Date: Tue Sep 2 10:43:24 2025 +0000

ntfs3: pretend $Extend records as regular files

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10d9947c580000
final oops: https://syzkaller.appspot.com/x/report.txt?x=12d9947c580000
console output: https://syzkaller.appspot.com/x/log.txt?x=14d9947c580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bdeb22...@syzkaller.appspotmail.com
Fixes: 4e8011ffec79 ("ntfs3: pretend $Extend records as regular files")

loop0: detected capacity change from 0 to 4096
ntfs3(loop0): Different NTFS sector size (4096) and media sector size (512).
INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 1 UID: 0 PID: 6038 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:984
register_lock_class+0x105/0x320 kernel/locking/lockdep.c:1299
__lock_acquire+0x99/0xd20 kernel/locking/lockdep.c:5112
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590
ntfs_set_size+0x140/0x200 fs/ntfs3/inode.c:860
ntfs_extend+0x1d9/0x970 fs/ntfs3/file.c:387
ntfs_setattr+0x2e8/0xbe0 fs/ntfs3/file.c:808
notify_change+0xc1a/0xf40 fs/attr.c:546
do_truncate+0x1a4/0x220 fs/open.c:68
vfs_truncate+0x493/0x520 fs/open.c:118
do_sys_truncate+0xdb/0x190 fs/open.c:141
__do_sys_truncate fs/open.c:153 [inline]
__se_sys_truncate fs/open.c:151 [inline]
__x64_sys_truncate+0x5b/0x70 fs/open.c:151
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f037f38eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff0b0c318 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f037f5d5fa0 RCX: 00007f037f38eba9
RDX: 0000000000000000 RSI: 00000000000003ff RDI: 0000200000000140
RBP: 00007f037f411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f037f5d5fa0 R14: 00007f037f5d5fa0 R15: 0000000000000002
</TASK>
ntfs3(loop0): ino=19, "file1" attr_set_size
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON(sem->magic != sem): count = 0x1, magic = 0x0, owner = 0xffff888075e03c80, curr 0xffff888075e03c80, list not empty
WARNING: kernel/locking/rwsem.c:1375 at __up_write kernel/locking/rwsem.c:1375 [inline], CPU#1: syz.0.17/6038
WARNING: kernel/locking/rwsem.c:1375 at up_write+0x2d1/0x420 kernel/locking/rwsem.c:1643, CPU#1: syz.0.17/6038
Modules linked in:
CPU: 1 UID: 0 PID: 6038 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__up_write kernel/locking/rwsem.c:1375 [inline]
RIP: 0010:up_write+0x2d1/0x420 kernel/locking/rwsem.c:1643
Code: c7 c7 00 ea aa 8b 48 c7 c6 60 eb aa 8b 48 8b 54 24 08 48 8b 0c 24 4c 8b 44 24 10 4d 89 e1 41 52 e8 54 57 e6 ff 48 83 c4 08 90 <0f> 0b 90 90 e9 a4 fd ff ff 90 0f 0b 90 e9 8c fe ff ff c6 05 09 ed
RSP: 0018:ffffc90002f878b8 EFLAGS: 00010286
RAX: 01d3ee795f15c600 RBX: ffff888058e20140 RCX: ffff888075e03c80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: dffffc0000000000 R08: ffffc90002f875c7 R09: 1ffff920005f0eb8
R10: dffffc0000000000 R11: fffff520005f0eb9 R12: ffff888075e03c80
R13: ffff888058e201a8 R14: 1ffff1100b1c4035 R15: ffff888058e20198
FS: 00005555647f8500(0000) GS:ffff888125ae8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32563fff CR3: 0000000073aba000 CR4: 00000000003526f0
Call Trace:
<TASK>
ntfs_set_size+0x172/0x200 fs/ntfs3/inode.c:865
ntfs_extend+0x1d9/0x970 fs/ntfs3/file.c:387
ntfs_setattr+0x2e8/0xbe0 fs/ntfs3/file.c:808
notify_change+0xc1a/0xf40 fs/attr.c:546
do_truncate+0x1a4/0x220 fs/open.c:68
vfs_truncate+0x493/0x520 fs/open.c:118
do_sys_truncate+0xdb/0x190 fs/open.c:141
__do_sys_truncate fs/open.c:153 [inline]
__se_sys_truncate fs/open.c:151 [inline]
__x64_sys_truncate+0x5b/0x70 fs/open.c:151
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f037f38eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff0b0c318 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f037f5d5fa0 RCX: 00007f037f38eba9
RDX: 0000000000000000 RSI: 00000000000003ff RDI: 0000200000000140
RBP: 00007f037f411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f037f5d5fa0 R14: 00007f037f5d5fa0 R15: 0000000000000002
</TASK>


---
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[Edward Adam Davis]

#syz test

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 3959f23c487a..180cd984339b 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -472,6 +472,7 @@ static struct inode *ntfs_read_mft(struct inode *inode,
/* Records in $Extend are not a files or general directories. */
inode->i_op = &ntfs_file_inode_operations;
mode = S_IFREG;
+ init_rwsem(&ni->file.run_lock);
} else {
err = -EINVAL;
goto out;

[Tetsuo Handa]

Well, we need to also initialize ni->file.run_lock, for vfs_truncate() now
passes the

/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
if (S_ISDIR(inode->i_mode))
return -EISDIR;
if (!S_ISREG(inode->i_mode))
return -EINVAL;

check. But do we really want to pretend as if S_IFREG ?

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 37cbbee7fa58..ea2193ebf8fc 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -471,6 +471,8 @@ static struct inode *ntfs_read_mft(struct inode *inode,
fname->home.seq == cpu_to_le16(MFT_REC_EXTEND)) {

/* Records in $Extend are not a files or general directories. */
inode->i_op = &ntfs_file_inode_operations;

+ mode = S_IFREG;

+ init_rwsem(&ni->file.run_lock);
} else {
err = -EINVAL;
goto out;

Are records in $Extend expected to be truncated to arbitrary size? Should we
prepend something other than S_IFREG (at least S_IFREG so that truncate()
will fail, or possibly S_IFSOCK so that open() will fail) ?

[syzbot]

Hello,

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

Reported-by: syzbot+bdeb22...@syzkaller.appspotmail.com
Tested-by: syzbot+bdeb22...@syzkaller.appspotmail.com

Tested on:

commit: c3067c2c Add linux-next specific files for 20250915
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1605fb62580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e269dbc7717119a2

dashboard link: https://syzkaller.appspot.com/bug?extid=bdeb22a4b9a09ab9aa45
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=104b8e42580000

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