syzbot

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refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 0 at lib/refcount.c:25 refcount_warn_saturate+0xf3/0x1b0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.6.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:refcount_warn_saturate+0xf3/0x1b0 lib/refcount.c:25
Code: 15 0a 01 0f 85 98 00 00 00 e8 39 41 66 fd 5b 41 5e c3 e8 30 41 66 fd c6 05 e1 00 15 0a 01 48 c7 c7 40 0f fc 8a e8 0d a5 30 fd <0f> 0b eb e0 e8 14 41 66 fd c6 05 c6 00 15 0a 01 48 c7 c7 a0 0f fc
RSP: 0018:ffffc90000007848 EFLAGS: 00010246
RAX: c472aa899118e200 RBX: 0000000000000002 RCX: ffffffff8ca93380
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc900000079d0 R08: ffffc90000007447 R09: 1ffff92000000e88
R10: dffffc0000000000 R11: fffff52000000e89 R12: ffff88802f861d40
R13: dffffc0000000000 R14: ffff88802f861e94 R15: ffff88801db63c00
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1106dddf98 CR3: 000000000cb30000 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:261 [inline]
 tipc_aead_encrypt net/tipc/crypto.c:821 [inline]
 tipc_crypto_xmit+0x17cf/0x2250 net/tipc/crypto.c:1761
 tipc_bearer_xmit_skb+0x246/0x3f0 net/tipc/bearer.c:572
 tipc_disc_timeout+0x581/0x6d0 net/tipc/discover.c:338
 call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x52d/0x7d0 kernel/time/timer.c:2022
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 63 10 42 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffffff8ca07d80 EFLAGS: 000002c2
RAX: c472aa899118e200 RBX: ffffffff81618a7b RCX: c472aa899118e200
RDX: 0000000000000001 RSI: ffffffff8aaab2c0 RDI: ffffffff8afc6780
RBP: ffffffff8ca07eb8 R08: ffff8880b8e36d4b R09: 1ffff110171c6da9
R10: dffffc0000000000 R11: ffffed10171c6daa R12: ffffffff8e49a768
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1952670
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:747
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 rest_init+0x2e2/0x300 init/main.c:732
 arch_call_rest_init+0xe/0x10 init/main.c:829
 start_kernel+0x459/0x4e0 init/main.c:1074
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>
----------------
Code disassembly (best guess):
   0:	cc                   	int3
   1:	cc                   	int3
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	cc                   	int3
   7:	f3 0f 1e fa          	endbr64
   b:	0f 0b                	ud2
   d:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  14:	00 00 00
  17:	f3 0f 1e fa          	endbr64
  1b:	66 90                	xchg   %ax,%ax
  1d:	0f 00 2d 63 10 42 00 	verw   0x421063(%rip)        # 0x421087
  24:	f3 0f 1e fa          	endbr64
  28:	fb                   	sti
  29:	f4                   	hlt
* 2a:	c3                   	ret <-- trapping instruction
  2b:	cc                   	int3
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	cc                   	int3
  31:	cc                   	int3
  32:	cc                   	int3
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	cc                   	int3
  37:	66 0f 1f 00          	nopw   (%rax)
  3b:	55                   	push   %rbp
  3c:	41 57                	push   %r15
  3e:	41 56                	push   %r14