[syzbot] [ntfs3?] WARNING in wnd_add_free_ext (4)

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Jun 19, 2025, 4:12:35 AM6/19/25
to almaz.ale...@paragon-software.com, linux-...@vger.kernel.org, nt...@lists.linux.dev, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 4663747812d1 Merge tag 'platform-drivers-x86-v6.16-2' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13f2750c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d11f52d3049c3790
dashboard link: https://syzkaller.appspot.com/bug?extid=323f07d372f692a127b3
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-46637478.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bde908b9f3d9/vmlinux-46637478.xz
kernel image: https://storage.googleapis.com/syzbot-assets/87a1193c8552/bzImage-46637478.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+323f07...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 4096
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 1
CPU: 0 UID: 0 PID: 5334 Comm: syz.0.0 Not tainted 6.16.0-rc2-syzkaller-00045-g4663747812d1 #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
fail_dump lib/fault-inject.c:73 [inline]
should_fail_ex+0x414/0x560 lib/fault-inject.c:174
should_failslab+0xa8/0x100 mm/failslab.c:46
slab_pre_alloc_hook mm/slub.c:4101 [inline]
slab_alloc_node mm/slub.c:4177 [inline]
kmem_cache_alloc_noprof+0x73/0x3c0 mm/slub.c:4204
wnd_remove_free_ext+0x902/0x11b0 fs/ntfs3/bitmap.c:476
wnd_zone_set+0x106/0x160 fs/ntfs3/bitmap.c:1396
ntfs_look_for_free_space+0x1cd/0x600 fs/ntfs3/fsntfs.c:383
attr_allocate_clusters+0x1c1/0x6d0 fs/ntfs3/attrib.c:159
attr_set_size+0x14a4/0x2c70 fs/ntfs3/attrib.c:574
ntfs_set_size+0x164/0x200 fs/ntfs3/inode.c:861
ntfs_extend+0x1d9/0x970 fs/ntfs3/file.c:343
ntfs_file_write_iter+0x3f4/0x820 fs/ntfs3/file.c:1192
iter_file_splice_write+0x937/0x1000 fs/splice.c:738
do_splice_from fs/splice.c:935 [inline]
direct_splice_actor+0x101/0x160 fs/splice.c:1158
splice_direct_to_actor+0x5a5/0xcc0 fs/splice.c:1102
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0x181/0x270 fs/splice.c:1227
do_sendfile+0x4da/0x7e0 fs/read_write.c:1370
__do_sys_sendfile64 fs/read_write.c:1425 [inline]
__se_sys_sendfile64+0xd9/0x190 fs/read_write.c:1417
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9976d8e929
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:00007f9977c79038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f9976fb5fa0 RCX: 00007f9976d8e929
RDX: 0000200000000080 RSI: 0000000000000005 RDI: 0000000000000005
RBP: 00007f9977c79090 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000e0000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000000000 R14: 00007f9976fb5fa0 R15: 00007ffc92c50238
</TASK>
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5334 at fs/ntfs3/bitmap.c:217 rb_insert_start fs/ntfs3/bitmap.c:217 [inline]
WARNING: CPU: 0 PID: 5334 at fs/ntfs3/bitmap.c:217 wnd_add_free_ext+0xafd/0xdb0 fs/ntfs3/bitmap.c:352
Modules linked in:
CPU: 0 UID: 0 PID: 5334 Comm: syz.0.0 Not tainted 6.16.0-rc2-syzkaller-00045-g4663747812d1 #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:rb_insert_start fs/ntfs3/bitmap.c:217 [inline]
RIP: 0010:wnd_add_free_ext+0xafd/0xdb0 fs/ntfs3/bitmap.c:352
Code: 00 00 fc ff df 42 80 3c 28 00 74 08 4c 89 f7 e8 99 a5 20 ff 49 89 1e 48 89 df 4c 89 e6 e8 bb 8f 5e 08 eb 18 e8 74 26 bd fe 90 <0f> 0b 90 49 bd 00 00 00 00 00 fc ff df 4c 8b 7c 24 10 48 8b 44 24
RSP: 0018:ffffc9000d247058 EFLAGS: 00010293
RAX: ffffffff830335cc RBX: ffff888052c3a600 RCX: ffff88801f7ea440
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00000000ffffffff R09: 0000000000000000
R10: ffff888052c3a600 R11: ffffffff81acf690 R12: ffff88801e8be2d8
R13: ffff888052c3a5a0 R14: 0000000000000003 R15: 0000000000000003
FS: 00007f9977c796c0(0000) GS:ffff88808d251000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f56af384000 CR3: 000000003f180000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
wnd_zone_set+0xb2/0x160 fs/ntfs3/bitmap.c:1393
ntfs_look_for_free_space+0x1cd/0x600 fs/ntfs3/fsntfs.c:383
attr_allocate_clusters+0x1c1/0x6d0 fs/ntfs3/attrib.c:159
attr_set_size+0x14a4/0x2c70 fs/ntfs3/attrib.c:574
ntfs_set_size+0x164/0x200 fs/ntfs3/inode.c:861
ntfs_extend+0x1d9/0x970 fs/ntfs3/file.c:343
ntfs_file_write_iter+0x3f4/0x820 fs/ntfs3/file.c:1192
iter_file_splice_write+0x937/0x1000 fs/splice.c:738
do_splice_from fs/splice.c:935 [inline]
direct_splice_actor+0x101/0x160 fs/splice.c:1158
splice_direct_to_actor+0x5a5/0xcc0 fs/splice.c:1102
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0x181/0x270 fs/splice.c:1227
do_sendfile+0x4da/0x7e0 fs/read_write.c:1370
__do_sys_sendfile64 fs/read_write.c:1425 [inline]
__se_sys_sendfile64+0xd9/0x190 fs/read_write.c:1417
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9976d8e929
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:00007f9977c79038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f9976fb5fa0 RCX: 00007f9976d8e929
RDX: 0000200000000080 RSI: 0000000000000005 RDI: 0000000000000005
RBP: 00007f9977c79090 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000e0000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000000000 R14: 00007f9976fb5fa0 R15: 00007ffc92c50238
</TASK>


---
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syzbot

unread,
Jan 27, 2026, 1:13:30 PMJan 27
to almaz.ale...@paragon-software.com, linux-...@vger.kernel.org, nt...@lists.linux.dev, syzkall...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: fcb70a56f4d8 Merge tag 'vfs-6.19-rc8.fixes' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14201fb3980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4aae00ac5a9d2645
dashboard link: https://syzkaller.appspot.com/bug?extid=323f07d372f692a127b3
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16c76bfa580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1741c98a580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-fcb70a56.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1800162cc24/vmlinux-fcb70a56.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a90ccad4f274/bzImage-fcb70a56.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/f27c3213c497/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/232aeef0d4ba/mount_5.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=17fd705a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+323f07...@syzkaller.appspotmail.com

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007fca63c16128 R14: 00007fca63c16090 R15: 00007ffedc73d3d8
</TASK>
------------[ cut here ]------------
1
WARNING: fs/ntfs3/bitmap.c:217 at rb_insert_start fs/ntfs3/bitmap.c:217 [inline], CPU#0: syz.0.18/5481
WARNING: fs/ntfs3/bitmap.c:217 at wnd_add_free_ext+0xb92/0xe60 fs/ntfs3/bitmap.c:352, CPU#0: syz.0.18/5481
Modules linked in:
CPU: 0 UID: 0 PID: 5481 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:rb_insert_start fs/ntfs3/bitmap.c:217 [inline]
RIP: 0010:wnd_add_free_ext+0xb92/0xe60 fs/ntfs3/bitmap.c:352
Code: 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 ff e8 44 8a 14 ff 4d 89 2f 4c 89 ef 48 89 de e8 b6 5e 7a 08 eb 0d e8 3f af aa fe 90 <0f> 0b 90 4c 8b 24 24 48 b8 00 00 00 00 00 fc ff df 48 8b 4c 24 30
RSP: 0018:ffffc90003f677c8 EFLAGS: 00010293
RAX: ffffffff8319d7b1 RBX: ffff88804437a2e0 RCX: ffff888000be8000
RDX: 0000000000000000 RSI: 0000000000000019 RDI: 0000000000000019
RBP: 0000000000000019 R08: ffff888047706c2b R09: 1ffff11008ee0d85
R10: dffffc0000000000 R11: ffffed1008ee0d86 R12: dffffc0000000000
R13: ffff88804a4c96c0 R14: ffff88804a5346c0 R15: 0000000000000019
FS: 00007fca648f46c0(0000) GS:ffff88808ccea000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fca648f3ff8 CR3: 0000000052ad1000 CR4: 0000000000352ef0
Call Trace:
<TASK>
wnd_set_free+0x4bf/0x5c0 fs/ntfs3/bitmap.c:743
mark_as_free_ex+0x1c8/0x390 fs/ntfs3/fsntfs.c:2489
run_unpack+0x7aa/0xc90 fs/ntfs3/run.c:1037
run_unpack_ex+0xd2/0xb90 fs/ntfs3/run.c:1078
ni_delete_all+0x363/0x8a0 fs/ntfs3/frecord.c:1562
ni_clear+0x315/0x530 fs/ntfs3/frecord.c:108
evict+0x61e/0xb10 fs/inode.c:837
do_unlinkat+0x354/0x590 fs/namei.c:5452
__do_sys_unlink fs/namei.c:5483 [inline]
__se_sys_unlink fs/namei.c:5481 [inline]
__x64_sys_unlink+0x47/0x50 fs/namei.c:5481
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fca6399aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fca648f4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007fca63c16090 RCX: 00007fca6399aeb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000180
RBP: 00007fca648f4090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007fca63c16128 R14: 00007fca63c16090 R15: 00007ffedc73d3d8
</TASK>


---
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