Subject: [syzbot] [apparmor?] linux-next test error: WARNING in apparmor_unix_stream_connect

From: syzbot <[email-masked]>
Date: Mon, 21 Jul 2025 02:35:31 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    979875200256 Add linux-next specific files for 20250721
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13bf7f98580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9baac92c2ceb707
dashboard link: https://syzkaller.appspot.com/bug?extid=cd38ee04bcb3866b0c6d
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9bf2232f3c8e/disk-97987520.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ae51e7da64a4/vmlinux-97987520.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e05ecb1741a9/bzImage-97987520.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

------------[ cut here ]------------
AppArmor WARN apparmor_unix_stream_connect: ((({ typeof(*(new_ctx->label)) *__UNIQUE_ID_rcu2213 = (typeof(*(new_ctx->label)) *)({ do { __attribute__((__noreturn__)) extern void __compiletime_assert_2214(void) __attribute__((__error__("Unsupported access size for {READ,WRITE}_ONCE()."))); if (!((sizeof((new_ctx->label)) == sizeof(char) || sizeof((new_ctx->label)) == sizeof(short) || sizeof((new_ctx->label)) == sizeof(int) || sizeof((new_ctx->label)) == sizeof(long)) || sizeof((new_ctx->label)) == sizeof(long long))) __compiletime_assert_2214(); } while (0); (*(const volatile typeof( _Generic(((new_ctx->label)), char: (char)0, unsigned char: (unsigned char)0, signed char: (signed char)0, unsigned short: (unsigned short)0, signed short: (signed short)0, unsigned int: (unsigned int)0, signed int: (signed int)0, unsigned long: (unsigned long)0, signed long: (signed long)0, unsigned long long: (unsigned long long)0, signed long long: (signed long long)0, default: ((new_ctx->label)))) *)&((new_ctx->label))); }); ; 
WARNING: security/apparmor/lsm.c:1211 at apparmor_unix_stream_connect+0x5fa/0x650 security/apparmor/lsm.c:1211, CPU#0: udevadm/5318
Modules linked in:
CPU: 0 UID: 0 PID: 5318 Comm: udevadm Not tainted 6.16.0-rc7-next-20250721-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:apparmor_unix_stream_connect+0x5fa/0x650 security/apparmor/lsm.c:1211
Code: 1c 3b fd 48 89 ef e8 35 4d 00 00 e9 09 fe ff ff e8 ab 1c 3b fd 90 48 c7 c7 40 31 fd 8b 48 c7 c6 2a 2e c7 8d e8 07 a4 fe fc 90 <0f> 0b 90 90 e9 27 fe ff ff e8 88 1c 3b fd be 02 00 00 00 eb 0a e8
RSP: 0018:ffffc90003367c38 EFLAGS: 00010246
RAX: 5674fa5d0d24c800 RBX: 1ffff1100fad97d0 RCX: ffff888026cd5a00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff88801ba8f8f8 R08: ffff8880b8624253 R09: 1ffff110170c484a
R10: dffffc0000000000 R11: ffffed10170c484b R12: ffff88807d6cbe80
R13: 1ffff1100fbc1bc8 R14: 0000000000000000 R15: 000000000000002f
FS:  00007f8de3bff880(0000) GS:ffff8881257a6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8de347ae00 CR3: 000000007fc96000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 security_unix_stream_connect+0xcb/0x2c0 security/security.c:4540
 unix_stream_connect+0x8fc/0x1010 net/unix/af_unix.c:1753
 __sys_connect_file net/socket.c:2086 [inline]
 __sys_connect+0x313/0x440 net/socket.c:2105
 __do_sys_connect net/socket.c:2111 [inline]
 __se_sys_connect net/socket.c:2108 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2108
 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: 0033:0x7f8de34a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc79327430 EFLAGS: 00000202 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f8de3bff880 RCX: 00007f8de34a7407
RDX: 0000000000000013 RSI: 000055d4ba7cf948 RDI: 0000000000000003
RBP: 000000000000001e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffc79327490
R13: 0000000000000000 R14: 0000000000000007 R15: 0000000000000000
 </TASK>

---
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 [email-masked].

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 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