------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 10643 at lib/refcount.c:25 refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 10643 Comm: dhcpcd 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: a6d2954d9de7dc00 RBX: 0000000000000002 RCX: ffff8880267a5940
RDX: 0000000000000100 RSI: 0000000000000101 RDI: 0000000000000000
RBP: ffffc900000079b0 R08: dffffc0000000000 R09: ffffed10172067a8
R10: ffffed10172067a8 R11: 1ffff110172067a7 R12: ffff888079278000
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cc1b1ca660 CR3: 00000000545a5000 CR4: 00000000003506f0
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:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:227 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x32/0x80 kernel/kcov.c:300
Code: b4 a9 8a 7e 65 8b 15 b5 a9 8a 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 83 b9 34 16 00 00 00 74 4e 8b 91 10 16 00 00 <83> fa 03 75 43 48 8b 91 18 16 00 00 44 8b 89 14 16 00 00 49 c1 e1
RSP: 0018:ffffc900033ef840 EFLAGS: 00000246
RAX: ffffffff81a18420 RBX: ffffea0002e46a80 RCX: ffff8880267a5940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: dffffc0000000000 R09: fffff940005c8d51
R10: fffff940005c8d51 R11: 1ffffd40005c8d50 R12: 00fff00000020036
R13: 0000000000000000 R14: ffffea0002e46a88 R15: 00fff00000020036
 mark_page_accessed+0x2a0/0x12b0 mm/swap.c:408
 zap_pte_range mm/memory.c:1381 [inline]
 zap_pmd_range mm/memory.c:1505 [inline]
 zap_pud_range mm/memory.c:1534 [inline]
 zap_p4d_range mm/memory.c:1555 [inline]
 unmap_page_range+0xe10/0x2520 mm/memory.c:1576
 unmap_vmas+0x11b/0x230 mm/memory.c:1653
 exit_mmap+0x38f/0x5f0 mm/mmap.c:3204
 __mmput+0x115/0x3b0 kernel/fork.c:1127
 exit_mm+0x567/0x6c0 kernel/exit.c:550
 do_exit+0x599/0x20a0 kernel/exit.c:861
 do_group_exit+0x12e/0x300 kernel/exit.c:996
 __do_sys_exit_group kernel/exit.c:1007 [inline]
 __se_sys_exit_group kernel/exit.c:1005 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1005
 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: 0033:0x7fecdded46c5
Code: Unable to access opcode bytes at RIP 0x7fecdded469b.
RSP: 002b:00007ffe5c19d588 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fecdded46c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000001
RBP: 00007ffe5c19db98 R08: 000055cc358c02c0 R09: 0000000000000002
R10: 00000000000000e0 R11: 0000000000000206 R12: 00007ffe5c19d5d0
R13: 000055cc358c1950 R14: 00007ffe5c19d810 R15: 00007ffe5c19d5c0
 </TASK>
----------------
Code disassembly (best guess):
   0:	b4 a9                	mov    $0xa9,%ah
   2:	8a 7e 65             	mov    0x65(%rsi),%bh
   5:	8b 15 b5 a9 8a 7e    	mov    0x7e8aa9b5(%rip),%edx        # 0x7e8aa9c0
   b:	81 e2 00 01 ff 00    	and    $0xff0100,%edx
  11:	74 11                	je     0x24
  13:	81 fa 00 01 00 00    	cmp    $0x100,%edx
  19:	75 57                	jne    0x72
  1b:	83 b9 34 16 00 00 00 	cmpl   $0x0,0x1634(%rcx)
  22:	74 4e                	je     0x72
  24:	8b 91 10 16 00 00    	mov    0x1610(%rcx),%edx
* 2a:	83 fa 03             	cmp    $0x3,%edx <-- trapping instruction
  2d:	75 43                	jne    0x72
  2f:	48 8b 91 18 16 00 00 	mov    0x1618(%rcx),%rdx
  36:	44 8b 89 14 16 00 00 	mov    0x1614(%rcx),%r9d
  3d:	49                   	rex.WB
  3e:	c1                   	.byte 0xc1
  3f:	e1                   	.byte 0xe1