Hello, I was writing some user code that uses the ptrace() system call and found it wasn't behaving as I expected. Maybe this is simply because I don't know enough about ptrace()'s behaviour, so I'd like someone to enlighten me with some information. So, here's the code: http://codepad.org/TJ7Lua4Q Basically, I was expecting the parent process to kill the child when the later attempted to use the kill() system call, not letting it send signals to other processes. I had done this before with pretty much the same code, but instead of killing when kill() was called, I was doing it when a fork() or clone() was attempted. And it worked. If the child process tried to create a new process via fork() or clone(), then it was immediately killed and no process was created. But now that I'm doing the same thing with kill(), I'm seeing that the child process ends up killed, as expected, but the signal is sent nonetheless. I understand that when I do the PTRACE_KILL, a SIGKILL signal is sent to the child. And PTRACE_KILL is used on syscall entrance in that code. If the SIGKILL signal is delivered to the process before it continues executing the system call in kernelspace, then I don't understand why this code doesn't work as expected. If the signal is delivered after the system call is completely executed, then I don't understand why this was working for the fork() and clone() case. I'd really appreciate if someone told me what's happening here, or what I'm not seeing. Thanks, -- Pablo Antonio (AKA crazy2k) http://www.pablo-a.com.ar/ _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
