BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1ef7fa067 P4D 1ef7fa067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 6405 Comm: syz.4.2226 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09cf0 EFLAGS: 00010206
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881c4053f00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e8f071c0
RBP: ffff8881f6f09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103ede1398 R11: 1ffff1103ede1398 R12: 00000000ffffc9b8
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e8f071c0
FS:  00007f8ae573f6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e4c49000 CR4: 00000000003406a0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
 expire_timers kernel/time/timer.c:1493 [inline]
 __run_timers+0x81d/0xb60 kernel/time/timer.c:1817
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
 __do_softirq+0x236/0x660 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x197/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:539 [inline]
 smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x3a/0x50 kernel/kcov.c:193
Code: 65 8b 15 95 0e a3 7e f7 c2 00 01 1f 00 74 02 5d c3 8b 91 00 0a 00 00 83 fa 02 75 f3 48 8b 91 08 0a 00 00 48 8b 32 48 8d 7e 01 <8b> 89 04 0a 00 00 48 39 cf 73 da 48 89 44 f2 08 48 89 3a 5d c3 90
RSP: 0018:ffff8881c7bd7890 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff83c70cf8 RBX: 0000000000000000 RCX: ffff8881c4053f00
RDX: ffffc9000795b000 RSI: 0000000000015026 RDI: 0000000000015027
RBP: ffff8881c7bd7890 R08: ffff8881c4053f00 R09: 000000000000000a
R10: 0000000000000015 R11: 0000000000000002 R12: ffff8881c7bd7a80
R13: ffff8881c6624000 R14: 0000000000000000 R15: 0000000000000011
 br_port_get_rtnl net/bridge/br_private.h:300 [inline]
 br_device_event+0x158/0x790 net/bridge/br.c:55
 notifier_call_chain kernel/notifier.c:98 [inline]
 __raw_notifier_call_chain kernel/notifier.c:399 [inline]
 raw_notifier_call_chain+0xa0/0x120 kernel/notifier.c:406
 call_netdevice_notifiers_info net/core/dev.c:1670 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:1682 [inline]
 call_netdevice_notifiers net/core/dev.c:1696 [inline]
 register_netdevice+0xb8a/0x12a0 net/core/dev.c:9204
 tun_set_iff+0x812/0xe00 drivers/net/tun.c:2922
 __tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470
 do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f8ae70d6969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8ae573f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8ae72fdfa0 RCX: 00007f8ae70d6969
RDX: 0000200000000040 RSI: 00000000400454ca RDI: 000000000000000d
RBP: 00007f8ae7158ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8ae72fdfa0 R15: 00007ffcf5ceb9d8
Modules linked in:
CR2: 0000000000000000
---[ end trace b118bd3d2f1bfda6 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09cf0 EFLAGS: 00010206
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881c4053f00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e8f071c0
RBP: ffff8881f6f09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103ede1398 R11: 1ffff1103ede1398 R12: 00000000ffffc9b8
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e8f071c0
FS:  00007f8ae573f6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e4c49000 CR4: 00000000003406a0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess):
   0:	65 8b 15 95 0e a3 7e 	mov    %gs:0x7ea30e95(%rip),%edx        # 0x7ea30e9c
   7:	f7 c2 00 01 1f 00    	test   $0x1f0100,%edx
   d:	74 02                	je     0x11
   f:	5d                   	pop    %rbp
  10:	c3                   	ret
  11:	8b 91 00 0a 00 00    	mov    0xa00(%rcx),%edx
  17:	83 fa 02             	cmp    $0x2,%edx
  1a:	75 f3                	jne    0xf
  1c:	48 8b 91 08 0a 00 00 	mov    0xa08(%rcx),%rdx
  23:	48 8b 32             	mov    (%rdx),%rsi
  26:	48 8d 7e 01          	lea    0x1(%rsi),%rdi
* 2a:	8b 89 04 0a 00 00    	mov    0xa04(%rcx),%ecx <-- trapping instruction
  30:	48 39 cf             	cmp    %rcx,%rdi
  33:	73 da                	jae    0xf
  35:	48 89 44 f2 08       	mov    %rax,0x8(%rdx,%rsi,8)
  3a:	48 89 3a             	mov    %rdi,(%rdx)
  3d:	5d                   	pop    %rbp
  3e:	c3                   	ret
  3f:	90                   	nop