------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 1 PID: 19265 at lib/refcount.c:153 refcount_inc_checked+0x5d/0x70 lib/refcount.c:153
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 19265 Comm: syz-executor1 Not tainted 4.20.0-rc7+ #156
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
SELinux: unrecognized netlink message: protocol=4 nlmsg_type=15 sclass=netlink_tcpdiag_socket pig=19272 comm=syz-executor3
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 panic+0x2ad/0x55c kernel/panic.c:188
 __warn.cold.8+0x20/0x45 kernel/panic.c:540
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:refcount_inc_checked+0x5d/0x70 lib/refcount.c:153
kobject: 'loop0' (00000000c87bda39): kobject_uevent_env
Code: 1d c2 bb 80 06 31 ff 89 de e8 8f 78 ed fd 84 db 75 df e8 b6 77 ed fd 48 c7 c7 40 b7 60 88 c6 05 a2 bb 80 06 01 e8 b3 d7 b6 fd <0f> 0b eb c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89
kobject: 'loop0' (00000000c87bda39): fill_kobj_path: path = '/devices/virtual/block/loop0'
RSP: 0018:ffff8881bc306ce0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90008362000
RDX: 000000000000f917 RSI: ffffffff8165e495 RDI: 0000000000000005
RBP: ffff8881bc306ce8 R08: ffff8881d2bc0080 R09: ffffed103b5e3ef8
R10: ffffed103b5e3ef8 R11: ffff8881daf1f7c7 R12: 0000000000000000
R13: 0000000100040b0b R14: ffff8881cbfd11c0 R15: dffffc0000000000
 igmp_start_timer+0xaf/0xe0 net/ipv4/igmp.c:214
 igmp_mod_timer net/ipv4/igmp.c:252 [inline]
 igmp_heard_query net/ipv4/igmp.c:1038 [inline]
 igmp_rcv+0x1a62/0x3220 net/ipv4/igmp.c:1073
kobject: 'loop5' (00000000e1bec0ea): kobject_uevent_env
kobject: 'loop5' (00000000e1bec0ea): fill_kobj_path: path = '/devices/virtual/block/loop5'
kobject: 'loop4' (00000000570b67e8): kobject_uevent_env
kobject: 'loop4' (00000000570b67e8): fill_kobj_path: path = '/devices/virtual/block/loop4'
 ip_local_deliver_finish+0x2e9/0xda0 net/ipv4/ip_input.c:215
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_local_deliver+0x1e9/0x750 net/ipv4/ip_input.c:256
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish+0x1f9/0x300 net/ipv4/ip_input.c:415
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_rcv+0xed/0x600 net/ipv4/ip_input.c:524
 __netif_receive_skb_one_core+0x14d/0x200 net/core/dev.c:4946
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:5056
 netif_receive_skb_internal+0x12c/0x800 net/core/dev.c:5159
 napi_frags_finish net/core/dev.c:5699 [inline]
 napi_gro_frags+0x75a/0xc90 net/core/dev.c:5772
 tun_get_user+0x3189/0x4250 drivers/net/tun.c:1952
kernel msg: ebtables bug: please report to author: Valid hook without chain
kobject: 'loop0' (00000000c87bda39): kobject_uevent_env
kobject: 'loop0' (00000000c87bda39): fill_kobj_path: path = '/devices/virtual/block/loop0'
 tun_chr_write_iter+0xb9/0x160 drivers/net/tun.c:1997
kobject: 'loop5' (00000000e1bec0ea): kobject_uevent_env
 call_write_iter include/linux/fs.h:1857 [inline]
 do_iter_readv_writev+0x8b0/0xa80 fs/read_write.c:680
 do_iter_write+0x185/0x5f0 fs/read_write.c:959
kobject: 'loop5' (00000000e1bec0ea): fill_kobj_path: path = '/devices/virtual/block/loop5'
 vfs_writev+0x1f1/0x360 fs/read_write.c:1004
 do_writev+0x11a/0x310 fs/read_write.c:1039
 __do_sys_writev fs/read_write.c:1112 [inline]
 __se_sys_writev fs/read_write.c:1109 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1109
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
kobject: 'loop5' (00000000e1bec0ea): kobject_uevent_env
RIP: 0033:0x457521
Code: 75 14 b8 14 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 b5 fb ff c3 48 83 ec 08 e8 1a 2d 00 00 48 89 04 24 b8 14 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 63 2d 00 00 48 89 d0 48 83 c4 08 48 3d 01
kobject: 'loop5' (00000000e1bec0ea): fill_kobj_path: path = '/devices/virtual/block/loop5'
RSP: 002b:00007fe43ce54ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000000002a RCX: 0000000000457521
RDX: 0000000000000001 RSI: 00007fe43ce54bf0 RDI: 00000000000000f0
RBP: 0000000020000640 R08: 00000000000000f0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007fe43ce556d4
R13: 00000000004c537d R14: 00000000004d9890 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..