[Question] Does fork mode executes LLVMFuzzerInitialize() each execution time?

[illera88]

Hi,

I have been reading the "fork mode" code and my understanding is that it will just call system() with some modifications from the original fuzzer arguments on as many threads as you indicate with -fork={threads}. But, maybe I'm missing something, but it looks like it does launch it from scratch each time and therefore calls LLVMFuzzerInitialize() which in my case is a very expensive function to call due to my target heavy initialization.
Am I right that LLVMFuzzerInitialize() is called per every execution?

I am in a situation in which I can't just return from a correct execution and:

• Normal mode in libfuzzer doesn't allow me to exit()
• Fork mode AFAIK does call LLVMFuzzerInitialize() on each thread on every execution.

Thank you for your help

[kcc]

I think you are correct, this is a per-process init and is called once per process.