I have a test program (see attached) that shows what looks like a bug in 2.6.5-1.358 (FedoraCore2)...and breaks my program :( In summary, I am doing: clone(run_thread, stack + sizeof(stack) -1, CLONE_FS|CLONE_FILES|CLONE_VM|SIGCHLD, NULL)) According to the man page the child process should have its own pid as returned by getpid()...much like fork(). In 2.6 the child receives the parent's pid from getpid(), while 2.4 works as documented: In 2.4 the test program does: parent pid: 26647 clone returned pid: 26648 thread reported pid: 26648 In 2.6 the test program does: parent pid: 16665 thread reported pid: 16665 clone returned pid: 16666 Is this fixed in later kernels? Thx Russ