------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 4163 at lib/refcount.c:25 refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 4163 Comm: udevd Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25
Code: 09 01 48 c7 c7 40 6b 59 8a e8 dd 27 bb 05 0f 0b eb e0 e8 04 42 9c fd c6 05 ae 8f 79 09 01 48 c7 c7 80 6a 59 8a e8 c1 27 bb 05 <0f> 0b eb c4 e8 e8 41 9c fd c6 05 93 8f 79 09 01 48 c7 c7 e0 6a 59
RSP: 0018:ffffc90000007848 EFLAGS: 00010246
RAX: ef2c56b396d27100 RBX: 0000000000000002 RCX: ffff888079ae9dc0
RDX: 0000000000000100 RSI: 0000000000000100 RDI: 0000000000000000
RBP: ffffc900000079b0 R08: dffffc0000000000 R09: fffff52000000e6d
R10: fffff52000000e6d R11: 1ffff92000000e6c R12: ffff88807d430000
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS:  00007f4bf0632880(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd950ce0ab8 CR3: 0000000072e59000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __refcount_add include/linux/refcount.h:-1 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 get_net include/net/net_namespace.h:252 [inline]
 tipc_aead_encrypt net/tipc/crypto.c:832 [inline]
 tipc_crypto_xmit+0x1949/0x2560 net/tipc/crypto.c:1772
 tipc_bearer_xmit_skb+0x228/0x3c0 net/tipc/bearer.c:574
 tipc_disc_timeout+0x568/0x6b0 net/tipc/discover.c:338
 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
 expire_timers kernel/time/timer.c:1496 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1767
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
 handle_softirqs+0x328/0x820 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202
Code: 66 2e 0f 1f 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 00 ec f0 0b 48 89 de 5b e9 47 ae 44 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 94 ad 8a 7e 65 8b 15 95 ad 8a 7e 81 e2 00
RSP: 0018:ffffc90002367a08 EFLAGS: 00000282
RAX: ffffffff83a234bc RBX: 0000000000000002 RCX: ffff888079ae9dc0
RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffffffff8a540340
RBP: 1ffff1100e8f43c3 R08: ffff888079ae9dc0 R09: 0000000000000003
R10: 000000000000000a R11: 0000000000000000 R12: ffffc90002367e40
R13: dffffc0000000000 R14: ffff8880747a1e18 R15: ffffffff8a540340
 aa_sock_msg_perm+0x6a/0x150 security/apparmor/lsm.c:949
 security_socket_sendmsg+0x6c/0xa0 security/security.c:2252
 __sock_sendmsg net/socket.c:713 [inline]
 ____sys_sendmsg+0x509/0x8c0 net/socket.c:2436
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg+0x190/0x250 net/socket.c:2526
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4bf0720407
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:00007ffd4e7c4eb0 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4bf0632880 RCX: 00007f4bf0720407
RDX: 0000000000000000 RSI: 00007ffd4e7c4f10 RDI: 000000000000000c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000066
R13: 00005610d6587f50 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
   7:	00 00 00
   a:	53                   	push   %rbx
   b:	48 89 fb             	mov    %rdi,%rbx
   e:	e8 17 00 00 00       	call   0x2a
  13:	48 8b 3d 00 ec f0 0b 	mov    0xbf0ec00(%rip),%rdi        # 0xbf0ec1a
  1a:	48 89 de             	mov    %rbx,%rsi
  1d:	5b                   	pop    %rbx
  1e:	e9 47 ae 44 00       	jmp    0x44ae6a
  23:	00 00                	add    %al,(%rax)
  25:	cc                   	int3
  26:	cc                   	int3
  27:	00 00                	add    %al,(%rax)
  29:	cc                   	int3
* 2a:	48 8b 04 24          	mov    (%rsp),%rax <-- trapping instruction
  2e:	65 48 8b 0d 94 ad 8a 	mov    %gs:0x7e8aad94(%rip),%rcx        # 0x7e8aadca
  35:	7e
  36:	65 8b 15 95 ad 8a 7e 	mov    %gs:0x7e8aad95(%rip),%edx        # 0x7e8aadd2
  3d:	81                   	.byte 0x81
  3e:	e2 00                	loop   0x40