------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 1 PID: 17532 at lib/refcount.c:156 refcount_inc_checked+0x4b/0x50 lib/refcount.c:156
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 17532 Comm: syz-executor.2 Not tainted 5.3.0-rc1+ #52
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x2f8 lib/dump_stack.c:113
 panic+0x29b/0x7d9 kernel/panic.c:219
 __warn+0x22f/0x230 kernel/panic.c:576
 report_bug+0x190/0x290 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 do_error_trap+0xd7/0x440 arch/x86/kernel/traps.c:272
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:291
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
RIP: 0010:refcount_inc_checked+0x4b/0x50 lib/refcount.c:156
Code: 3d b8 a7 93 05 01 75 08 e8 c2 d6 10 fe 5b 5d c3 e8 ba d6 10 fe c6 05 a2 a7 93 05 01 48 c7 c7 d9 4c 88 88 31 c0 e8 95 ec e1 fd <0f> 0b eb df 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0
RSP: 0018:ffff8880aeb09b40 EFLAGS: 00010246
RAX: 55a2a32874c4b900 RBX: ffff8880a1577500 RCX: ffff88808959e2c0
RDX: 0000000000000301 RSI: 0000000000000301 RDI: 0000000000000000
RBP: ffff8880aeb09b48 R08: ffffffff816063f4 R09: fffffbfff119a92f
R10: fffffbfff119a92f R11: 0000000000000000 R12: ffff888093cb4c40
R13: dffffc0000000000 R14: 0000000000000004 R15: ffff8880a1577480
 sock_hold include/net/sock.h:649 [inline]
 sk_add_node include/net/sock.h:701 [inline]
 nr_insert_socket net/netrom/af_netrom.c:137 [inline]
 nr_rx_frame+0x17bc/0x1e40 net/netrom/af_netrom.c:1023
 nr_loopback_timer+0x6a/0x140 net/netrom/nr_loopback.c:59
 call_timer_fn+0xec/0x200 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers+0x7cd/0x9c0 kernel/time/timer.c:1685
 run_timer_softirq+0x4a/0x90 kernel/time/timer.c:1698
 __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:778
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x227/0x230 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:537 [inline]
 smp_apic_timer_interrupt+0x113/0x280 arch/x86/kernel/apic/apic.c:1095
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
 </IRQ>
RIP: 0010:check_kcov_mode kernel/kcov.c:68 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x14/0x50 kernel/kcov.c:102
Code: 00 00 00 48 8b 3d 74 0b 86 07 48 89 de e8 94 38 3a 00 5b 5d c3 90 48 8b 04 24 65 48 8b 0c 25 40 fd 01 00 65 8b 15 f8 20 8a 7e <f7> c2 00 01 1f 00 75 2c 8b 91 f0 12 00 00 83 fa 02 75 21 48 8b 91
RSP: 0018:ffff8880880376d8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: ffffffff8791b035 RBX: 00000000000000fd RCX: ffff88808959e2c0
RDX: 0000000080000000 RSI: 00000000000000fd RDI: 0000000000000002
RBP: ffff888088037730 R08: ffffffff8791af24 R09: 0000000000000000
R10: fffffbfff11fbcb5 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880a5a9a590 R14: ffff8880a38c7500 R15: ffff8880a38c7500
 batadv_hardif_add_interface net/batman-adv/hard-interface.c:942 [inline]
 batadv_hard_if_event+0xb91/0xed0 net/batman-adv/hard-interface.c:1032
 notifier_call_chain kernel/notifier.c:95 [inline]
 __raw_notifier_call_chain kernel/notifier.c:396 [inline]
 raw_notifier_call_chain+0xec/0x190 kernel/notifier.c:403
 call_netdevice_notifiers_info net/core/dev.c:1749 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:1761 [inline]
 call_netdevice_notifiers net/core/dev.c:1775 [inline]
 register_netdevice+0xfe9/0x1500 net/core/dev.c:8752
 __ip_tunnel_create+0x2a0/0x360 net/ipv4/ip_tunnel.c:269
 ip_tunnel_init_net+0x205/0x6c0 net/ipv4/ip_tunnel.c:1060
 erspan_init_net+0x29/0x30 net/ipv4/ip_gre.c:1589
 ops_init+0x355/0x430 net/core/net_namespace.c:137
 setup_net+0x230/0x7e0 net/core/net_namespace.c:334
 copy_net_ns+0x2f9/0x460 net/core/net_namespace.c:475
 create_new_namespaces+0x4ec/0x700 kernel/nsproxy.c:103
 unshare_nsproxy_namespaces+0x12a/0x190 kernel/nsproxy.c:202
 ksys_unshare+0x544/0xac0 kernel/fork.c:2831
 __do_sys_unshare kernel/fork.c:2899 [inline]
 __se_sys_unshare kernel/fork.c:2897 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:2897
 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9a0190bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9a0190c6d4
R13: 00000000004c8f0a R14: 00000000004dff80 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..