Autoloading module: intpm.ko Starting background file system checks in 60 seconds. Fri May 31 23:15 FreeBSD/amd64 (ci-freebsd-main-0.c.syzkaller.internal) (ttyu0) Warning: Permanently added '10.128.0.57' (ECDSA) to the list of known hosts. 2019/05/31 23:16:09 parsed 1 programs 2019/05/31 23:16:09 executed programs: 0 login: interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type interface if_tuntap.1 already present in the KLD 'kernel'! linker_load_file: /boot/kernel/if_tap.ko - unsupported file type panic: mtx_lock() of spin mutex (null) @ /syzkaller/managers/main/kernel/sys/netinet/tcp_output.c:337 cpuid = 0 time = 1559344570 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe001f6c2550 vpanic() at vpanic+0x1e0/frame 0xfffffe001f6c25b0 panic() at panic+0x43/frame 0xfffffe001f6c2610 __mtx_lock_flags() at __mtx_lock_flags+0x1fd/frame 0xfffffe001f6c2670 tcp_output() at tcp_output+0x5ee/frame 0xfffffe001f6c2830 tcp_usr_connect() at tcp_usr_connect+0x25c/frame 0xfffffe001f6c2880 soconnectat() at soconnectat+0x183/frame 0xfffffe001f6c28e0 kern_connectat() at kern_connectat+0x1ff/frame 0xfffffe001f6c2940 sys_connect() at sys_connect+0xd9/frame 0xfffffe001f6c2980 amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe001f6c2ab0 fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe001f6c2ab0 --- syscall (198, FreeBSD ELF64, nosys), rip = 0x41311a, rsp = 0x7fffdfffdf38, rbp = 0x3 --- KDB: enter: panic [ thread pid 836 tid 100122 ] Stopped at kdb_enter+0x6a: movq $0,kdb_why