PT KAFL crashes at start

[k-sareen]

I've been trying to get the pt_kafl branch to work, specifically the version that disassembles and decodes the stream of PT packets (afl-fuzz with afl-pt-proxy from my understanding), however it always crashes at run_target in afl-fuzz.c [1].

It seems like the fork server is not writing to the correct file descriptor (if at all). Inspecting in gdb, it informs me that res is 0, so the write never actually happens. The weird part is that pt-fuzz-fast and pt-proxy-fast don't seem to have the issue and seem to fuzz fine. I've gone through the diffs of both to see if the fork server does something different for the *-fast versions, but I don't immediately see anything different. Would you have any ideas as to where the issue is happening?

Thanks,
Kunal
[1]: https://github.com/junxzm1990/afl-pt/blob/pt_kafl/afl-2.42b/afl-fuzz.c#L2480

[k-sareen]

I have ported the glibc patch to glibc-2.27 (I've just applied your patch to rtld.c for glibc-2.27 and it seems to work) , so it might be that the rtld is causing issues specifically with the afl-fuzz version but I don't think that really makes sense as the *-fast version all work.