Autoloading module: intpm.ko Starting background file system checks in 60 seconds. Mon Mar 18 19:11 FreeBSD/amd64 (ci-freebsd-main-9.c.syzkaller.internal) (ttyu0) Warning: Permanently added '10.128.0.211' (ECDSA) to the list of known hosts. 2019/03/18 19:11:13 parsed 1 programs 2019/03/18 19:11:13 executed programs: 0 login: panic: mtx_lock() of spin mutex (null) @ /syzkaller/managers/main/kernel/sys/netinet/tcp_output.c:337 cpuid = 0 time = 1552936273 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe001fa5e530 vpanic() at vpanic+0x1e0/frame 0xfffffe001fa5e590 panic() at panic+0x43/frame 0xfffffe001fa5e5f0 __mtx_lock_flags() at __mtx_lock_flags+0x1fd/frame 0xfffffe001fa5e650 tcp_output() at tcp_output+0x62a/frame 0xfffffe001fa5e810 tcp6_usr_connect() at tcp6_usr_connect+0x3b6/frame 0xfffffe001fa5e880 soconnectat() at soconnectat+0x183/frame 0xfffffe001fa5e8e0 kern_connectat() at kern_connectat+0x1ff/frame 0xfffffe001fa5e940 sys_connect() at sys_connect+0xd9/frame 0xfffffe001fa5e980 amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe001fa5eab0 fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe001fa5eab0 --- syscall (198, FreeBSD ELF64, nosys), rip = 0x412e5a, rsp = 0x7fffdfffdf38, rbp = 0x3 --- KDB: enter: panic [ thread pid 771 tid 100114 ] Stopped at kdb_enter+0x6a: movq $0,kdb_why