https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=2986a524d853ab6d06bf88b65e0e9d60cea51dcc
commit 2986a524d853ab6d06bf88b65e0e9d60cea51dcc Author: Michael Haubenwallner <[email protected]> Date: Wed Jul 31 12:35:33 2019 +0200 Cygwin: fork: attach child not before success Do not attach to the child before it was successfully initialized, or we would need more sophisticated cleanup on child initialization failure, like suppressing SIGCHILD delivery with multiple threads ("waitproc") involved. Improves "Cygwin: fork: Remember child not before success.", commit f03ea8e1c57bd5cea83f6cd47fa02870bdfeb1c5, which leads to fork problems if cygserver is running: https://cygwin.com/ml/cygwin-patches/2019-q2/msg00155.html Diff: --- winsup/cygwin/fork.cc | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc index 0119581..7080144 100644 --- a/winsup/cygwin/fork.cc +++ b/winsup/cygwin/fork.cc @@ -424,14 +424,6 @@ frok::parent (volatile char * volatile stack_here) #endif goto cleanup; } - if (!child.reattach ()) - { - this_errno = EAGAIN; -#ifdef DEBUGGING0 - error ("child reattach failed"); -#endif - goto cleanup; - } /* CHILD IS STOPPED */ debug_printf ("child is alive (but stopped)"); @@ -516,6 +508,17 @@ frok::parent (volatile char * volatile stack_here) } } + /* Do not attach to the child before it has successfully initialized. + Otherwise we may wait forever, or deliver an orphan SIGCHILD. */ + if (!child.reattach ()) + { + this_errno = EAGAIN; +#ifdef DEBUGGING0 + error ("child reattach failed"); +#endif + goto cleanup; + } + /* Finally start the child up. */ resume_child (forker_finished);
