[patch] Hangs and/or multithreaded process left Stopped (T) on CTRL-C of strace

[Roland McGrath]

What is <unistd.h> for?

tcp->parent->pid is wrong when there are -f fork children (not threads).
I believe that with your patch:
	(sleep 5; exec sh -c 'sleep 10; sleep 10') & strace -f -p $!
	# wait > 5sec
	^C
will do a wrong tgkill to the sleep process, passing tgid of sh instead,
get ESRCH and block in wait4 having sent no SIGSTOP.

I think the tgid arg needs to be:
	(tcp->flags & TCB_CLONE_THREAD) ? tcp->parent->pid : tcp->pid


Thanks,
Roland