netlink: 'syz-executor4': attribute type 4 has an invalid length. netlink: 'syz-executor4': attribute type 4 has an invalid length. ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 32234 at lib/refcount.c:187 refcount_sub_and_test_checked+0x2c9/0x310 lib/refcount.c:187 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 32234 Comm: syz-executor4 Not tainted 4.20.0-rc3+ #314 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+0x244/0x39d lib/dump_stack.c:113 kobject: 'tunl0' (0000000055d5a2ee): kobject_cleanup, parent (null) kobject: 'tunl0' (0000000055d5a2ee): auto cleanup 'remove' event panic+0x2ad/0x55c kernel/panic.c:188 kobject: 'tunl0' (0000000055d5a2ee): kobject_uevent_env kobject: 'tunl0' (0000000055d5a2ee): kobject_uevent_env: uevent_suppress caused the event to drop! __warn.cold.8+0x20/0x45 kernel/panic.c:540 kobject: 'tunl0' (0000000055d5a2ee): calling ktype release 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 kobject: 'tunl0': free name invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969 RIP: 0010:refcount_sub_and_test_checked+0x2c9/0x310 lib/refcount.c:187 Code: 89 de e8 8a 1c ed fd 84 db 74 07 31 db e9 4d ff ff ff e8 aa 1b ed fd 48 c7 c7 20 b2 60 88 c6 05 49 62 80 06 01 e8 f7 7b b6 fd <0f> 0b 31 db e9 2c ff ff ff 48 89 cf e8 26 6b 30 fe e9 41 fe ff ff RSP: 0018:ffff8881c2096a60 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8165eaf5 RDI: 0000000000000005 RBP: ffff8881c2096b48 R08: ffff8881920642c0 R09: ffffed103b5e5020 R10: ffffed103b5e5020 R11: ffff8881daf28107 R12: ffff8881994aa23c R13: 00000000ffff0001 R14: ffff8881c2096b20 R15: ffff8881cc0453c0 sock_wfree+0xb8/0x180 net/core/sock.c:1821 sctp_wfree+0x3a8/0xb40 net/sctp/socket.c:8586 skb_release_head_state+0x15f/0x2e0 net/core/skbuff.c:612 skb_release_all+0x15/0x60 net/core/skbuff.c:625 __kfree_skb net/core/skbuff.c:641 [inline] consume_skb+0x1ae/0x570 net/core/skbuff.c:701 sctp_chunk_destroy net/sctp/sm_make_chunk.c:1462 [inline] sctp_chunk_put+0x2d4/0x450 net/sctp/sm_make_chunk.c:1489 sctp_datamsg_destroy net/sctp/chunk.c:128 [inline] sctp_datamsg_put+0x28b/0x620 net/sctp/chunk.c:145 sctp_chunk_free+0x46/0x60 net/sctp/sm_make_chunk.c:1474 __sctp_outq_teardown+0x37d/0x11f0 net/sctp/outqueue.c:234 sctp_outq_free+0x15/0x20 net/sctp/outqueue.c:291 sctp_association_free+0x2f0/0x972 net/sctp/associola.c:361 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:939 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1353 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline] sctp_do_sm+0x4a32/0x7180 net/sctp/sm_sideeffect.c:1191 sctp_primitive_ABORT+0xa0/0xd0 net/sctp/primitive.c:119 sctp_close+0x278/0xad0 net/sctp/socket.c:1540 inet_release+0x104/0x1f0 net/ipv4/af_inet.c:428 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:458 __sock_release+0xd7/0x250 net/socket.c:579 sock_close+0x19/0x20 net/socket.c:1141 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411021 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffe8ecab5b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000411021 RDX: 0000000000000000 RSI: 0000000000730d10 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00007ffe8ecab4e0 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 00000000000001a6 R15: 0000000000000004 Kernel Offset: disabled Rebooting in 86400 seconds..