[syzbot] [ntfs3?] BUG: unable to handle kernel NULL pointer dereference in ntfs_sparse_cluster

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e2ca6ba6ba01 Merge tag 'mm-stable-2022-12-13' of git://git..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=122e9bc7880000
kernel config: https://syzkaller.appspot.com/x/.config?x=276eb8ff64eb2c27
dashboard link: https://syzkaller.appspot.com/bug?extid=deb631beeb93bdb2df4c
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10d8601b880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17a09c93880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8aad47431ccd/disk-e2ca6ba6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/382636835ba9/vmlinux-e2ca6ba6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ac62c9f6a7cf/bzImage-e2ca6ba6.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2d4fa4df0bbf/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+deb631...@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 217c0067 P4D 217c0067 PUD 1e4e8067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5302 Comm: syz-executor244 Not tainted 6.1.0-syzkaller-09941-ge2ca6ba6ba01 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90003c1fca8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff8880268b8000
RDX: 0000000000000000 RSI: ffffea0001c79440 RDI: ffff888075eb0478
RBP: ffffea0001c79440 R08: ffffffff81bc12ab R09: fffff9400038f289
R10: fffff9400038f289 R11: 1ffffd400038f288 R12: 0000000000000000
R13: 0000000000010000 R14: 1ffffd400038f288 R15: ffffffffffffffff
FS: 00007f45fe7d4700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000002986e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ntfs_sparse_cluster+0x767/0xa90 fs/ntfs3/file.c:335
ntfs_fallocate+0xbc6/0xfb0 fs/ntfs3/file.c:727
vfs_fallocate+0x515/0x670 fs/open.c:323
ksys_fallocate fs/open.c:346 [inline]
__do_sys_fallocate fs/open.c:354 [inline]
__se_sys_fallocate fs/open.c:352 [inline]
__x64_sys_fallocate+0xb9/0x100 fs/open.c:352
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f4606a484c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f45fe7d4308 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f4606aec6f8 RCX: 00007f4606a484c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007f4606aec6f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000010000 R11: 0000000000000246 R12: 00007f4606aec6fc
R13: 00007f4606ab93d8 R14: 0030656c69662f2e R15: 0000000000022000
</TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90003c1fca8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff8880268b8000
RDX: 0000000000000000 RSI: ffffea0001c79440 RDI: ffff888075eb0478
RBP: ffffea0001c79440 R08: ffffffff81bc12ab R09: fffff9400038f289
R10: fffff9400038f289 R11: 1ffffd400038f288 R12: 0000000000000000
R13: 0000000000010000 R14: 1ffffd400038f288 R15: ffffffffffffffff
FS: 00007f45fe7d4700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000002986e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

syzbot suspects this issue was fixed by commit:

commit c380b52f6c5702cc4bdda5e6d456d6c19a201a0b
Author: Konstantin Komarov <almaz.ale...@paragon-software.com>
Date: Fri Oct 7 11:02:36 2022 +0000

fs/ntfs3: Change new sparse cluster processing

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1377b979480000
start commit: e2ca6ba6ba01 Merge tag 'mm-stable-2022-12-13' of git://git..
git tree: upstream

kernel config: https://syzkaller.appspot.com/x/.config?x=276eb8ff64eb2c27
dashboard link: https://syzkaller.appspot.com/bug?extid=deb631beeb93bdb2df4c

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10d8601b880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17a09c93880000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fs/ntfs3: Change new sparse cluster processing

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Dmitry Vyukov]

Looks reasonable, let's close the bug so that syzbot reports similar
bugs in future: