------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 1 PID: 8280 at lib/refcount.c:156 refcount_inc_checked lib/refcount.c:156 [inline]
WARNING: CPU: 1 PID: 8280 at lib/refcount.c:156 refcount_inc_checked+0x61/0x70 lib/refcount.c:154
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 8280 Comm: syz-executor.3 Not tainted 5.3.0-rc2+ #93
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 5e 90 64 06 31 ff 89 de e8 eb 99 35 fe 84 db 75 dd e8 a2 98 35 fe 48 c7 c7 80 03 c6 87 c6 05 3e 90 64 06 01 e8 57 05 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:ffff8880ae909bf0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000100 RSI: ffffffff815c5216 RDI: ffffed1015d21370
RBP: ffff8880ae909c00 R08: ffff88806a16c040 R09: ffffed1015d260d1
R10: ffffed1015d260d0 R11: ffff8880ae930687 R12: ffff88806f47eb00
R13: ffff88806f47eae8 R14: ffff88806ca8ccc8 R15: ffff88806ca8cca0
 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 20 f2 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 15 32 95 01 00 74 20 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 32 0f 11 fa 65 8b 05 e3 3d c4 78 85 c0 74 06 41
RSP: 0018:ffff888079cfefe0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11a5e44 RBX: ffff88806a16c040 RCX: 1ffffffff134b3de
RDX: dffffc0000000000 RSI: ffffffff81781bae RDI: ffffffff873dbfe8
RBP: ffff888079cfefe8 R08: ffff88806a16c040 R09: ffffed1015d26ad1
R10: ffffed1015d26ad0 R11: ffff8880ae935683 R12: ffff8880ae935680
R13: ffff8880883d2340 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
 io_schedule+0x1c/0x70 kernel/sched/core.c:5600
 bit_wait_io+0x17/0xa0 kernel/sched/wait_bit.c:208
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd8/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 __wait_on_buffer fs/buffer.c:119 [inline]
 wait_on_buffer include/linux/buffer_head.h:354 [inline]
 __sync_dirty_buffer+0x29b/0x350 fs/buffer.c:3188
 sync_dirty_buffer+0x1b/0x20 fs/buffer.c:3200
 ext4_write_inode+0x54b/0x600 fs/ext4/inode.c:5455
 write_inode fs/fs-writeback.c:1224 [inline]
 __writeback_single_inode+0xd67/0x13f0 fs/fs-writeback.c:1423
 writeback_single_inode+0x2cc/0x430 fs/fs-writeback.c:1477
 sync_inode fs/fs-writeback.c:2514 [inline]
 sync_inode_metadata+0xa8/0xe0 fs/fs-writeback.c:2534
 __generic_file_fsync+0x169/0x200 fs/libfs.c:1007
 ext4_sync_file+0x89a/0x15c0 fs/ext4/fsync.c:120
 vfs_fsync_range+0x141/0x230 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2793 [inline]
 ext4_file_write_iter+0x839/0x1430 fs/ext4/file.c:281
 call_write_iter include/linux/fs.h:1870 [inline]
 do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x184/0x610 fs/read_write.c:951
 vfs_iter_write+0x77/0xb0 fs/read_write.c:983
 iter_file_splice_write+0x66d/0xbe0 fs/splice.c:746
 do_splice_from fs/splice.c:848 [inline]
 direct_splice_actor+0x123/0x190 fs/splice.c:1020
 splice_direct_to_actor+0x366/0x970 fs/splice.c:975
 do_splice_direct+0x1da/0x2a0 fs/splice.c:1063
 do_sendfile+0x597/0xd00 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1519 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0x15a/0x220 fs/read_write.c:1511
 do_syscall_64+0xfd/0x6a0 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:00007f888ed86c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459829
RDX: 0000000020000000 RSI: 0000000000000007 RDI: 0000000000000007
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 00007f888ed876d4
R13: 00000000004c6ff7 R14: 00000000004dc558 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..