[v6.6] linux-6.6.y test error: general protection fault in fgetxattr

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 08667c1437c0 Linux 6.6.132
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11fb7aba580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=09d67970d561cc40ed26
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/694f9fa6e328/disk-08667c14.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/45192f000768/vmlinux-08667c14.xz
kernel image: https://storage.googleapis.com/syzbot-assets/528a65d2f078/bzImage-08667c14.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+09d679...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000030: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000180-0x0000000000000187]
CPU: 1 PID: 5906 Comm: syz.2.129 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:file_mnt_idmap include/linux/fs.h:2481 [inline]
RIP: 0010:__do_sys_fgetxattr fs/xattr.c:814 [inline]
RIP: 0010:__se_sys_fgetxattr+0x132/0x370 fs/xattr.c:808
Code: 89 fe e8 d1 33 8e ff 45 85 ff 0f 84 23 02 00 00 e8 13 30 8e ff eb 05 e8 0c 30 8e ff 4c 8d bb 80 01 00 00 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 cf 66 e6 ff 4d 8b 27 49 83 c4 18
RSP: 0018:ffffc9000498fd00 EFLAGS: 00010206
RAX: 0000000000000030 RBX: 0000000000000000 RCX: ffff88803136bc00
RDX: 0000000000000000 RSI: 0000000000000100 RDI: 00000000ffffffff
RBP: ffffc9000498ff10 R08: ffff88807b1a61c3 R09: 1ffff1100f634c38
R10: dffffc0000000000 R11: ffffed100f634c39 R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff92000931fac R15: 0000000000000180
FS: 0000555564d1e500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa4d6f2ba40 CR3: 000000002f847000 CR4: 00000000003506e0
Call Trace:
<TASK>
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa4d6f9c819
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:00007fff29ca4158 EFLAGS: 00000246 ORIG_RAX: 00000000000000c1
RAX: ffffffffffffffda RBX: 00007fa4d7215fa0 RCX: 00007fa4d6f9c819
RDX: 0000200000000000 RSI: 0000200000000000 RDI: ffffffffffffffff
RBP: 00007fa4d7032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa4d7215fac R14: 00007fa4d7215fa0 R15: 00007fa4d7215fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:file_mnt_idmap include/linux/fs.h:2481 [inline]
RIP: 0010:__do_sys_fgetxattr fs/xattr.c:814 [inline]
RIP: 0010:__se_sys_fgetxattr+0x132/0x370 fs/xattr.c:808
Code: 89 fe e8 d1 33 8e ff 45 85 ff 0f 84 23 02 00 00 e8 13 30 8e ff eb 05 e8 0c 30 8e ff 4c 8d bb 80 01 00 00 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 cf 66 e6 ff 4d 8b 27 49 83 c4 18
RSP: 0018:ffffc9000498fd00 EFLAGS: 00010206
RAX: 0000000000000030 RBX: 0000000000000000 RCX: ffff88803136bc00
RDX: 0000000000000000 RSI: 0000000000000100 RDI: 00000000ffffffff
RBP: ffffc9000498ff10 R08: ffff88807b1a61c3 R09: 1ffff1100f634c38
R10: dffffc0000000000 R11: ffffed100f634c39 R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff92000931fac R15: 0000000000000180
FS: 0000555564d1e500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c914a71e28 CR3: 000000002f847000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
0: 89 fe mov %edi,%esi
2: e8 d1 33 8e ff call 0xff8e33d8
7: 45 85 ff test %r15d,%r15d
a: 0f 84 23 02 00 00 je 0x233
10: e8 13 30 8e ff call 0xff8e3028
15: eb 05 jmp 0x1c
17: e8 0c 30 8e ff call 0xff8e3028
1c: 4c 8d bb 80 01 00 00 lea 0x180(%rbx),%r15
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 ff mov %r15,%rdi
34: e8 cf 66 e6 ff call 0xffe66708
39: 4d 8b 27 mov (%r15),%r12
3c: 49 83 c4 18 add $0x18,%r12


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