------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 7423 at lib/refcount.c:25 refcount_warn_saturate+0xf3/0x1b0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 7423 Comm: syz-executor 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: 650f7d46d172d300 RBX: 0000000000000002 RCX: ffff8880268a5a00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc900000079d0 R08: ffffc90000007447 R09: 1ffff92000000e88
R10: dffffc0000000000 R11: fffff52000000e89 R12: ffff88807b723a80
R13: dffffc0000000000 R14: ffff88807b723bd4 R15: ffff88802eaa5800
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000006a227000 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:check_kcov_mode kernel/kcov.c:184 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x30/0x60 kernel/kcov.c:216
Code: 04 24 65 48 8b 0d 10 23 7e 7e 65 8b 15 11 23 7e 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48
RSP: 0018:ffffc90004ab76e8 EFLAGS: 00000246
RAX: ffffffff813aafe4 RBX: 0000000080000000 RCX: ffff8880268a5a00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc90004ab77c0 R08: ffff8880268a5a00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc90004ab7828
R13: dffffc0000000000 R14: ffffc90004ab7828 R15: ffffc90004ab7838
 unwind_next_frame+0x1d24/0x2970 arch/x86/kernel/unwind_orc.c:672
 __unwind_start+0x66a/0x7e0 arch/x86/kernel/unwind_orc.c:760
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:128
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
 vfree+0x1a6/0x320 mm/vmalloc.c:2860
 kcov_put kernel/kcov.c:438 [inline]
 kcov_close+0x2b/0x50 kernel/kcov.c:534
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x903/0x23c0 kernel/exit.c:874
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1023
 __do_sys_exit_group kernel/exit.c:1034 [inline]
 __se_sys_exit_group kernel/exit.c:1032 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1032
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4d0df8e929
Code: Unable to access opcode bytes at 0x7f4d0df8e8ff.
RSP: 002b:00007ffcb8fc4de8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f4d0df8e929
RDX: 00007f4d0df8d3a0 RSI: 0000000000000004 RDI: 0000000000000001
RBP: 00007f4d0e1b6738 R08: 00007ffcb8fc2b87 R09: 0000000000000008
R10: 0000000000000019 R11: 0000000000000246 R12: 0000000000000008
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	04 24                	add    $0x24,%al
   2:	65 48 8b 0d 10 23 7e 	mov    %gs:0x7e7e2310(%rip),%rcx        # 0x7e7e231a
   9:	7e
   a:	65 8b 15 11 23 7e 7e 	mov    %gs:0x7e7e2311(%rip),%edx        # 0x7e7e2322
  11:	81 e2 00 01 ff 00    	and    $0xff0100,%edx
  17:	74 11                	je     0x2a
  19:	81 fa 00 01 00 00    	cmp    $0x100,%edx
  1f:	75 35                	jne    0x56
  21:	83 b9 1c 16 00 00 00 	cmpl   $0x0,0x161c(%rcx)
  28:	74 2c                	je     0x56
* 2a:	8b 91 f8 15 00 00    	mov    0x15f8(%rcx),%edx <-- trapping instruction
  30:	83 fa 02             	cmp    $0x2,%edx
  33:	75 21                	jne    0x56
  35:	48 8b 91 00 16 00 00 	mov    0x1600(%rcx),%rdx
  3c:	48 8b 32             	mov    (%rdx),%rsi
  3f:	48                   	rex.W