------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 0 PID: 5372 at lib/refcount.c:153 refcount_inc_checked lib/refcount.c:153 [inline]
WARNING: CPU: 0 PID: 5372 at lib/refcount.c:153 refcount_inc_checked+0x61/0x70 lib/refcount.c:151
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 5372 Comm: syz-executor.3 Not tainted 5.0.0-rc5+ #78
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 panic+0x2cb/0x65c kernel/panic.c:214
 __warn.cold+0x20/0x45 kernel/panic.c:571
 report_bug+0x263/0x2b0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 fixup_bug arch/x86/kernel/traps.c:173 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:refcount_inc_checked lib/refcount.c:153 [inline]
RIP: 0010:refcount_inc_checked+0x61/0x70 lib/refcount.c:151
Code: 1d 7c e6 2e 06 31 ff 89 de e8 0b ec 45 fe 84 db 75 dd e8 c2 ea 45 fe 48 c7 c7 a0 26 a2 87 c6 05 5c e6 2e 06 01 e8 fd 3b 19 fe <0f> 0b eb c1 90 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41
RSP: 0018:ffff8880985ff348 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000010d19 RSI: ffffffff815a8c66 RDI: ffffed10130bfe5b
RBP: ffff8880985ff358 R08: ffff88809b81a000 R09: ffffed1015d03ef9
R10: ffffed1015d03ef8 R11: ffff8880ae81f7c7 R12: ffff88808f66280c
R13: ffff88808f6627c0 R14: 0000000000000000 R15: ffff88808f662780
 igmp_start_timer+0xac/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+0x18ed/0x29b0 net/ipv4/igmp.c:1073
 ip_protocol_deliver_rcu+0x60/0x8e0 net/ipv4/ip_input.c:208
 ip_local_deliver_finish+0x23b/0x390 net/ipv4/ip_input.c:234
 NF_HOOK include/linux/netfilter.h:289 [inline]
 NF_HOOK include/linux/netfilter.h:283 [inline]
 ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:255
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish+0x1db/0x2f0 net/ipv4/ip_input.c:414
 NF_HOOK include/linux/netfilter.h:289 [inline]
 NF_HOOK include/linux/netfilter.h:283 [inline]
 ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:524
 __netif_receive_skb_one_core+0x115/0x1a0 net/core/dev.c:4973
 __netif_receive_skb+0x2c/0x1c0 net/core/dev.c:5083
 netif_receive_skb_internal+0x117/0x660 net/core/dev.c:5186
 napi_frags_finish net/core/dev.c:5753 [inline]
 napi_gro_frags+0xade/0xd10 net/core/dev.c:5827
 tun_get_user+0x2832/0x38d0 drivers/net/tun.c:1974
 tun_chr_write_iter+0xbd/0x160 drivers/net/tun.c:2019
 call_write_iter include/linux/fs.h:1863 [inline]
 do_iter_readv_writev+0x5e0/0x8e0 fs/read_write.c:680
 do_iter_write fs/read_write.c:956 [inline]
 do_iter_write+0x184/0x610 fs/read_write.c:937
 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1001
 do_writev+0xf6/0x290 fs/read_write.c:1036
kobject: 'loop5' (00000000ced58165): kobject_uevent_env
 __do_sys_writev fs/read_write.c:1109 [inline]
 __se_sys_writev fs/read_write.c:1106 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1106
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457ce1
kobject: 'loop5' (00000000ced58165): fill_kobj_path: path = '/devices/virtual/block/loop5'
Code: 75 14 b8 14 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 e4 b9 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
RSP: 002b:00007f4e776dcba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000000002a RCX: 0000000000457ce1
RDX: 0000000000000001 RSI: 00007f4e776dcbf0 RDI: 00000000000000f0
RBP: 0000000020000240 R08: 00000000000000f0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f4e776dd6d4
R13: 00000000004c6477 R14: 00000000004db8c0 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..