[v6.1] kernel BUG in ntfs_attr_extend_allocation

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3db754f56897 Linux 6.1.152
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11cf3b12580000
kernel config: https://syzkaller.appspot.com/x/.config?x=68aa5a3af1cb953a
dashboard link: https://syzkaller.appspot.com/bug?extid=c43cda6a24b6cd83e3ba
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9b92862bd95a/disk-3db754f5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f232864105d7/vmlinux-3db754f5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/30a3ed81e30f/Image-3db754f5.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c43cda...@syzkaller.appspotmail.com

loop2: detected capacity change from 0 to 4096
ntfs: volume version 3.1.
------------[ cut here ]------------
kernel BUG at fs/ntfs/attrib.c:1956!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 5184 Comm: syz.2.98 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ntfs_attr_extend_allocation+0x2ab4/0x33e0 fs/ntfs/attrib.c:1956
lr : ntfs_attr_extend_allocation+0x2ab4/0x33e0 fs/ntfs/attrib.c:1956
sp : ffff800022667720
x29: ffff800022667870 x28: dfff800000000000 x27: ffff0000cffc5080
x26: 8000000000000000 x25: ffff0000cffc5088 x24: 7fffffffffffffff
x23: ffff0000f5ff0070 x22: 1ffff0000388d1a0 x21: ffffffffffffffff
x20: 0000000000001000 x19: ffff0000f5ff0000 x18: ffff800011abbcc0
x17: ffff8000181fa000 x16: ffff8000082d22e0 x15: 0000000000000002
x14: 00000000ffff8000 x13: 0000000010f9ded2 x12: 0000000000080000
x11: 000000000000bd74 x10: ffff800026e8b000 x9 : ffff800009523244
x8 : 000000000000bd75 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : 0000000000000001 x3 : ffffffffffffffff
x2 : 7fffffffffffffff x1 : 8000000000000000 x0 : 7fffffffffffffff
Call trace:
ntfs_attr_extend_allocation+0x2ab4/0x33e0 fs/ntfs/attrib.c:1956
ntfs_truncate+0x9a0/0x2138 fs/ntfs/inode.c:2682
ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
ntfs_setattr+0x260/0x320 fs/ntfs/inode.c:2914
notify_change+0xb0c/0xdcc fs/attr.c:499
do_truncate+0x178/0x1f0 fs/open.c:65
vfs_truncate+0x23c/0x2b0 fs/open.c:111
do_sys_truncate+0xe8/0x1b0 fs/open.c:134
__do_sys_truncate fs/open.c:146 [inline]
__se_sys_truncate fs/open.c:144 [inline]
__arm64_sys_truncate+0x5c/0x70 fs/open.c:144
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d4210000 97bdfa43 d4210000 97bdfa41 (d4210000)
---[ end trace 0000000000000000 ]---


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 3db754f56897 Linux 6.1.152
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1745147c580000

kernel config: https://syzkaller.appspot.com/x/.config?x=68aa5a3af1cb953a
dashboard link: https://syzkaller.appspot.com/bug?extid=c43cda6a24b6cd83e3ba
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1180bb12580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=122f7934580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9b92862bd95a/disk-3db754f5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f232864105d7/vmlinux-3db754f5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/30a3ed81e30f/Image-3db754f5.gz.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/6d2373a0a285/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c43cda...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 4096

ntfs: volume version 3.1.
------------[ cut here ]------------
kernel BUG at fs/ntfs/attrib.c:1956!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:

CPU: 1 PID: 4521 Comm: syz.0.17 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ntfs_attr_extend_allocation+0x2ab4/0x33e0 fs/ntfs/attrib.c:1956
lr : ntfs_attr_extend_allocation+0x2ab4/0x33e0 fs/ntfs/attrib.c:1956

sp : ffff800021287720
x29: ffff800021287870 x28: dfff800000000000 x27: ffff0000d2bba080
x26: 8000000000000000 x25: ffff0000d2bba088 x24: 7fffffffffffffff
x23: ffff0000f1c073f0 x22: 1ffff0000388d1a0 x21: ffffffffffffffff
x20: 0000000000001000 x19: ffff0000f1c07380 x18: ffff800011abbcc0
x17: ffff8000181fa000 x16: ffff8000082d22e0 x15: ffff80000898c9a4
x14: ffff80000898c880 x13: ffff800008059270 x12: 0000000000ff0100
x11: ff00800009523244 x10: 0000000000000000 x9 : ffff800009523244
x8 : ffff0000d1fa3780 x7 : ffff80000805948c x6 : ffff80000805969c
x5 : ffff0000dc9ff868 x4 : ffff8000212875b0 x3 : ffffffffffffffff

x2 : 7fffffffffffffff x1 : 8000000000000000 x0 : 7fffffffffffffff
Call trace:
ntfs_attr_extend_allocation+0x2ab4/0x33e0 fs/ntfs/attrib.c:1956
ntfs_truncate+0x9a0/0x2138 fs/ntfs/inode.c:2682
ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
ntfs_setattr+0x260/0x320 fs/ntfs/inode.c:2914
notify_change+0xb0c/0xdcc fs/attr.c:499
do_truncate+0x178/0x1f0 fs/open.c:65
vfs_truncate+0x23c/0x2b0 fs/open.c:111
do_sys_truncate+0xe8/0x1b0 fs/open.c:134
__do_sys_truncate fs/open.c:146 [inline]
__se_sys_truncate fs/open.c:144 [inline]
__arm64_sys_truncate+0x5c/0x70 fs/open.c:144
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d4210000 97bdfa43 d4210000 97bdfa41 (d4210000)
---[ end trace 0000000000000000 ]---


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