------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 0 PID: 9930 at lib/refcount.c:156 refcount_inc_checked lib/refcount.c:156 [inline]
WARNING: CPU: 0 PID: 9930 at lib/refcount.c:156 refcount_inc_checked+0x61/0x70 lib/refcount.c:154
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9930 Comm: syz-executor094 Not tainted 5.3.0-rc1+ #84
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+0x172/0x1f0 lib/dump_stack.c:113
 panic+0x2dc/0x755 kernel/panic.c:219
 __warn.cold+0x20/0x4c kernel/panic.c:576
 report_bug+0x263/0x2b0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
RIP: 0010:refcount_inc_checked lib/refcount.c:156 [inline]
RIP: 0010:refcount_inc_checked+0x61/0x70 lib/refcount.c:154
Code: 1d 18 8e 64 06 31 ff 89 de e8 db aa 35 fe 84 db 75 dd e8 92 a9 35 fe 48 c7 c7 00 03 c6 87 c6 05 f8 8d 64 06 01 e8 77 0c 07 fe <0f> 0b eb c1 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41
RSP: 0018:ffff8880ae809bf0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000100 RSI: ffffffff815c5bd6 RDI: ffffed1015d01370
RBP: ffff8880ae809c00 R08: ffff8880a4384400 R09: fffffbfff11b4285
R10: fffffbfff11b4284 R11: ffffffff88da1423 R12: ffff88809d5933c0
R13: ffff88809d5933a8 R14: ffff88808b998288 R15: ffff88808b998260
 sock_hold include/net/sock.h:649 [inline]
 sk_add_node include/net/sock.h:701 [inline]
 nr_insert_socket+0x2d/0xe0 net/netrom/af_netrom.c:137
 nr_rx_frame+0x1605/0x1e73 net/netrom/af_netrom.c:1023
 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:537 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1095
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x54/0x90 kernel/locking/spinlock.c:199
Code: c0 a0 f1 d2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 33 48 83 3d c5 04 95 01 00 74 20 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 32 e2 10 fa 65 8b 05 93 10 c4 78 85 c0 74 06 41
RSP: 0018:ffff8880a8dc7b20 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11a5e34 RBX: ffff8880a4384400 RCX: 1ffffffff134b2b6
RDX: dffffc0000000000 RSI: ffffffff8178256e RDI: ffffffff873decb8
RBP: ffff8880a8dc7b28 R08: ffff8880a4384400 R09: ffffed1015d06ab1
R10: ffffed1015d06ab0 R11: ffff8880ae835583 R12: ffff8880ae835580
R13: ffff88808b91a080 R14: 0000000000000000 R15: 0000000000000001
 finish_lock_switch kernel/sched/core.c:3004 [inline]
 finish_task_switch+0x147/0x720 kernel/sched/core.c:3104
 context_switch kernel/sched/core.c:3257 [inline]
 __schedule+0x75d/0x1580 kernel/sched/core.c:3880
 schedule+0xa8/0x270 kernel/sched/core.c:3944
 freezable_schedule include/linux/freezer.h:172 [inline]
 do_nanosleep+0x201/0x6a0 kernel/time/hrtimer.c:1679