[Android 5.10] general protection fault in mnt_want_write (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 58c592510fcd Merge 5.10.248 into android13-5.10-lts
git tree: android13-5.10-lts
console output: https://syzkaller.appspot.com/x/log.txt?x=1178a65a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ef167f989dba92e
dashboard link: https://syzkaller.appspot.com/bug?extid=13dff099f2731732743b
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=10adab22580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c667fa580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5f658524a370/disk-58c59251.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ef9f5387b57b/vmlinux-58c59251.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e1f18f7534a/bzImage-58c59251.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+13dff0...@syzkaller.appspotmail.com

incfs: Can't find or create .incomplete dir in ./file0
incfs: mount failed -22
incfs: ino conflict with backing FS 2
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 359 Comm: syz.2.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:mnt_want_write+0x2f/0x270 fs/namespace.c:363
Code: 57 41 56 41 55 41 54 53 50 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 b0 43 b6 ff 48 89 5d d0 48 83 c3 08 49 89 de 49 c1 ee 03 <43> 80 3c 2e 00 74 08 48 89 df e8 32 c1 f0 ff 4c 8b 3b 4d 8d a7 a8
RSP: 0018:ffffc90000c77ad0 EFLAGS: 00010202
RAX: ffffffff81ae7220 RBX: 0000000000000008 RCX: ffff8881101c93c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000c77b00 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200018ee34 R12: ffff88810d374770
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
FS: 000055555562c500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000010fd6d000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ovl_want_write+0x92/0xa0 fs/overlayfs/util.c:21
ovl_setattr+0x4a/0x720 fs/overlayfs/inode.c:28
notify_change+0xab3/0xe40 fs/attr.c:410
incfs_setattr+0x246/0x3c0 fs/incfs/vfs.c:1664
notify_change+0xab3/0xe40 fs/attr.c:410
chmod_common+0x1e1/0x390 fs/open.c:584
do_fchmodat+0xd4/0x1a0 fs/open.c:622
__do_sys_chmod fs/open.c:640 [inline]
__se_sys_chmod fs/open.c:638 [inline]
__x64_sys_chmod+0x60/0x70 fs/open.c:638
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7ffa3751feb9
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:00007ffd20e6d988 EFLAGS: 00000246 ORIG_RAX: 000000000000005a
RAX: ffffffffffffffda RBX: 00007ffa3779afa0 RCX: 00007ffa3751feb9
RDX: 0000000000000000 RSI: 0000000000000054 RDI: 0000200000000000
RBP: 00007ffa3758dc1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffa3779afac R14: 00007ffa3779afa0 R15: 00007ffa3779afa0
Modules linked in:
---[ end trace 7d35ea90ef849765 ]---
RIP: 0010:mnt_want_write+0x2f/0x270 fs/namespace.c:363
Code: 57 41 56 41 55 41 54 53 50 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 b0 43 b6 ff 48 89 5d d0 48 83 c3 08 49 89 de 49 c1 ee 03 <43> 80 3c 2e 00 74 08 48 89 df e8 32 c1 f0 ff 4c 8b 3b 4d 8d a7 a8
RSP: 0018:ffffc90000c77ad0 EFLAGS: 00010202
RAX: ffffffff81ae7220 RBX: 0000000000000008 RCX: ffff8881101c93c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000c77b00 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200018ee34 R12: ffff88810d374770
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
FS: 000055555562c500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c005734000 CR3: 000000010fd6d000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 57 push %rdi
1: 41 56 push %r14
3: 41 55 push %r13
5: 41 54 push %r12
7: 53 push %rbx
8: 50 push %rax
9: 48 89 fb mov %rdi,%rbx
c: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13
13: fc ff df
16: e8 b0 43 b6 ff call 0xffb643cb
1b: 48 89 5d d0 mov %rbx,-0x30(%rbp)
1f: 48 83 c3 08 add $0x8,%rbx
23: 49 89 de mov %rbx,%r14
26: 49 c1 ee 03 shr $0x3,%r14
* 2a: 43 80 3c 2e 00 cmpb $0x0,(%r14,%r13,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 48 89 df mov %rbx,%rdi
34: e8 32 c1 f0 ff call 0xfff0c16b
39: 4c 8b 3b mov (%rbx),%r15
3c: 4d rex.WRB
3d: 8d .byte 0x8d
3e: a7 cmpsl %es:(%rdi),%ds:(%rsi)
3f: a8 .byte 0xa8


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup