--- wikisrc/tutorials/how_to_enable_and_run_dtrace.mdwn 2019/07/21 12:28:26 1.27 +++ wikisrc/tutorials/how_to_enable_and_run_dtrace.mdwn 2020/03/30 15:40:27 1.28 @@ -151,3 +151,19 @@ made by a process - `execsnoop` - snoop on execution of processes as they occur - `opensnoop` - snoop on openning of files as they occur - `procsystime` - print process system call time details. + +## Troubleshooting + +The Compact C Type Format (CTF) has a 2^15 limit on types which can overflow, this prevents DTrace from +working correctly. + +Check the number of types using `ctfdump` e.g + ctfdump -S /netbsd + +Note the line which states `total number of types`, the value should by less than 32768. + +If overflow is not an issue, `libdtrace(3)` can provide some insight into what is going on via an +environment variable. Define `DTRACE_DEBUG` before tracing. + + env DTRACE_DEBUG= execsnoop +