------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 4871 at lib/refcount.c:25 refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 4871 Comm: kworker/u4:14 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: bat_events batadv_nc_worker
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:ffffc90000dd0848 EFLAGS: 00010246
RAX: 4e109a56e71e1300 RBX: 0000000000000002 RCX: ffff888026070000
RDX: 0000000000000100 RSI: 0000000000000100 RDI: 0000000000000000
RBP: ffffc90000dd09b0 R08: dffffc0000000000 R09: fffff520001ba06d
R10: fffff520001ba06d R11: 1ffff920001ba06c R12: ffff888021bccf80
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb9dcff0e9c CR3: 000000000be8e000 CR4: 00000000003506e0
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:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x132/0x1b0 kernel/softirq.c:408
Code: 8a e8 42 1c 59 08 65 66 8b 05 1a 37 bb 7e 66 85 c0 75 54 bf 01 00 00 00 e8 6b fe 08 00 e8 76 7e 35 00 fb 65 8b 05 06 0e ba 7e <85> c0 75 05 e8 b5 18 b8 ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc9000382faa0 EFLAGS: 00000286
RAX: 0000000080000000 RBX: 0000000000000201 RCX: 4e109a56e71e1300
RDX: dffffc0000000000 RSI: ffffffff8a0b11c0 RDI: ffffffff8a59a740
RBP: ffffc9000382fb38 R08: dffffc0000000000 R09: fffffbfff1ff3637
R10: fffffbfff1ff3637 R11: 1ffffffff1ff3636 R12: ffffffff897732e6
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff92000705f54
 spin_unlock_bh include/linux/spinlock.h:408 [inline]
 batadv_nc_purge_paths+0x316/0x3b0 net/batman-adv/network-coding.c:475
 batadv_nc_worker+0x2e7/0x5c0 net/batman-adv/network-coding.c:724
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
----------------
Code disassembly (best guess):
   0:	8a e8                	mov    %al,%ch
   2:	42 1c 59             	rex.X sbb $0x59,%al
   5:	08 65 66             	or     %ah,0x66(%rbp)
   8:	8b 05 1a 37 bb 7e    	mov    0x7ebb371a(%rip),%eax        # 0x7ebb3728
   e:	66 85 c0             	test   %ax,%ax
  11:	75 54                	jne    0x67
  13:	bf 01 00 00 00       	mov    $0x1,%edi
  18:	e8 6b fe 08 00       	call   0x8fe88
  1d:	e8 76 7e 35 00       	call   0x357e98
  22:	fb                   	sti
  23:	65 8b 05 06 0e ba 7e 	mov    %gs:0x7eba0e06(%rip),%eax        # 0x7eba0e30
* 2a:	85 c0                	test   %eax,%eax <-- trapping instruction
  2c:	75 05                	jne    0x33
  2e:	e8 b5 18 b8 ff       	call   0xffb818e8
  33:	48 c7 04 24 0e 36 e0 	movq   $0x45e0360e,(%rsp)
  3a:	45
  3b:	4b                   	rex.WXB
  3c:	c7                   	.byte 0xc7
  3d:	04 37                	add    $0x37,%al