kernel BUG in ntfs_attr_extend_allocation

Status: upstream: reported C repro on 2025/09/15 06:46
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+c43cda6a24b6cd83e3ba@syzkaller.appspotmail.com
First crash: 313d, last: 298d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/09/16 linux-6.1.y (ToT) 3db754f56897 C [report] kernel BUG in ntfs_attr_extend_allocation
2025/09/16 upstream (ToT) 46a51f4f5eda C Didn't crash
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/09/28 11:41 1h57m fix candidate upstream OK (0) job log

Sample crash report:
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: 0 PID: 4490 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 : ffff800020907720
x29: ffff800020907870 x28: dfff800000000000 x27: ffff0000dd40a080
x26: 8000000000000000 x25: ffff0000dd40a088 x24: 7fffffffffffffff
x23: ffff0000e9b573f0 x22: 1ffff0000388d1a0 x21: ffffffffffffffff
x20: 0000000000001000 x19: ffff0000e9b57380 x18: ffff800011abbcc0
x17: ffff8000181fa000 x16: ffff8000082d22e0 x15: ffff80000898c9a4
x14: ffff80000898c880 x13: ffff800008059270 x12: 0000000000ff0100
x11: ff00800009523244 x10: 0000000000000000 x9 : ffff800009523244
x8 : ffff0000d7799bc0 x7 : ffff80000805948c x6 : ffff80000805969c
x5 : ffff0000d9e88408 x4 : ffff8000209075b0 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 ]---

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/15 08:24 linux-6.1.y 3db754f56897 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 kernel BUG in ntfs_attr_extend_allocation
2025/09/15 07:51 linux-6.1.y 3db754f56897 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 kernel BUG in ntfs_attr_extend_allocation
2025/09/15 07:19 linux-6.1.y 3db754f56897 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 kernel BUG in ntfs_attr_extend_allocation
2025/09/30 13:38 linux-6.1.y 7b34dc04e4ff 86341da6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 kernel BUG in ntfs_attr_extend_allocation
2025/09/15 06:45 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 kernel BUG in ntfs_attr_extend_allocation
* Struck through repros no longer work on HEAD.