------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28, CPU#0: syz.0.2245/14127
Modules linked in:
CPU: 0 UID: 0 PID: 14127 Comm: syz.0.2245 Not tainted 6.16.0-rc2-next-20250618-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Code: e0 7d e2 8b e8 c7 a2 c0 fc 90 0f 0b 90 90 eb d7 e8 6b f1 fc fc c6 05 76 0b c8 0a 01 90 48 c7 c7 40 7e e2 8b e8 a7 a2 c0 fc 90 <0f> 0b 90 90 eb b7 e8 4b f1 fc fc c6 05 53 0b c8 0a 01 90 48 c7 c7
RSP: 0018:ffffc90000007b88 EFLAGS: 00010246
RAX: 9b40fd615fc25e00 RBX: 0000000000000003 RCX: ffff8880341c9e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90000007c90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfaa14 R12: 1ffff92000000f78
R13: ffff888034db5968 R14: ffff888034db5820 R15: 0000000000000000
FS:  00007f219067b6c0(0000) GS:ffff888125c3d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001140 CR3: 000000003357c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2372 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
 run_timer_base kernel/time/timer.c:2393 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:begin_current_label_crit_section+0x0/0x1e0 security/apparmor/include/cred.h:168
Code: fd be 01 00 00 00 48 89 df e8 ac 38 43 00 e9 36 ff ff ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 53 49 bf 00 00 00 00 00 fc ff df e8 eb 2a 40 fd e8
RSP: 0018:ffffc9001abbf8b8 EFLAGS: 00000282
RAX: 1ffff1100d76ec5d RBX: ffff88806406e810 RCX: ffff8880341c9e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88806bb761c0
RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000
R10: ffff88806406e800 R11: fffffbfff1f42d9f R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88806bb762e8 R15: dffffc0000000000
 apparmor_file_alloc_security+0x48/0x110 security/apparmor/lsm.c:506
 security_file_alloc+0x14b/0x330 security/security.c:2862
 init_file+0x93/0x2f0 fs/file_table.c:159
 alloc_empty_file+0x6e/0x1d0 fs/file_table.c:241
 path_openat+0x107/0x3830 fs/namei.c:4032
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1434
 do_sys_open fs/open.c:1449 [inline]
 __do_sys_openat fs/open.c:1465 [inline]
 __se_sys_openat fs/open.c:1460 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1460
 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: 0033:0x7f218f78d290
Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 49 94 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 9c 94 02 00 8b 44
RSP: 002b:00007f219067af10 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f218f78d290
RDX: 0000000000000002 RSI: 00007f219067afa0 RDI: 00000000ffffff9c
RBP: 00007f219067afa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f218f9b6080 R15: 00007ffc38804158
 </TASK>
----------------
Code disassembly (best guess):
   0:	fd                   	std
   1:	be 01 00 00 00       	mov    $0x1,%esi
   6:	48 89 df             	mov    %rbx,%rdi
   9:	e8 ac 38 43 00       	call   0x4338ba
   e:	e9 36 ff ff ff       	jmp    0xffffff49
  13:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	90                   	nop
  21:	90                   	nop
  22:	90                   	nop
  23:	90                   	nop
  24:	90                   	nop
  25:	90                   	nop
  26:	90                   	nop
  27:	90                   	nop
  28:	90                   	nop
  29:	90                   	nop
* 2a:	55                   	push   %rbp <-- trapping instruction
  2b:	41 57                	push   %r15
  2d:	41 56                	push   %r14
  2f:	53                   	push   %rbx
  30:	49 bf 00 00 00 00 00 	movabs $0xdffffc0000000000,%r15
  37:	fc ff df
  3a:	e8 eb 2a 40 fd       	call   0xfd402b2a
  3f:	e8                   	.byte 0xe8