6 files changed, 25 insertions, 4 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 202331dac53..b2773ddbf50 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,15 @@
+2013-06-23  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Try to avoid malloc SEGVs on Cygwin (Bug#14569).
+        * callproc.c, process.h (block_child_signal, unblock_child_signal):
+        Now extern.
+        * emacs.c (main): Catch SIGCHLD just before initializing gfilenotify.
+        * process.c (catch_child_signal): Block SIGCHLD while futzing with
+        the SIGCHLD handler, since the code is not atomic and (due to glib)
+        signals may be arriving now.
+        * sysdep.c (init_signals): Do not catch child signals here;
+        'main' now does that later, at a safer time.
+
 2013-06-22  Paul Eggert  <eggert@cs.ucla.edu>
 
         Clean up SIGCHLD handling a bit (Bug#14569).
diff --git a/src/callproc.c b/src/callproc.c
index 745d58c45f4..f0aa8222342 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -84,7 +84,7 @@ static int synch_process_fd;
 
 /* Block SIGCHLD.  */
 
-static void
+void
 block_child_signal (void)
 {
   sigset_t blocked;
@@ -95,7 +95,7 @@ block_child_signal (void)
 
 /* Unblock SIGCHLD.  */
 
-static void
+void
 unblock_child_signal (void)
 {
   pthread_sigmask (SIG_SETMASK, &empty_mask, 0);
diff --git a/src/emacs.c b/src/emacs.c
index 13f6d117ebc..c5b32c7c0e7 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -1257,6 +1257,13 @@ Using an Emacs configured with --with-x-toolkit=lucid does not have this problem
     tzset ();
 #endif /* MSDOS */
 
+  /* Do this after initializing the memory allocator, since it uses
+     glib and glib uses malloc.  And do it before anything else that
+     invokes glib, to avoid potential races among glib subthreads in
+     Cygwin glib.  gfilenotify invokes glib, so this can't be delayed
+     further.  */
+  catch_child_signal ();
+
 #ifdef HAVE_GFILENOTIFY
   globals_of_gfilenotify ();
 #endif
diff --git a/src/process.c b/src/process.c
index 3e31dede4c2..6df1bf7eff7 100644
--- a/src/process.c
+++ b/src/process.c
@@ -7084,11 +7084,13 @@ catch_child_signal (void)
 #endif
 
   emacs_sigaction_init (&action, deliver_child_signal);
+  block_child_signal ();
   sigaction (SIGCHLD, &action, &old_action);
   eassert (! (old_action.sa_flags & SA_SIGINFO));
   if (old_action.sa_handler != SIG_DFL && old_action.sa_handler != SIG_IGN
       && old_action.sa_handler != deliver_child_signal)
     lib_child_handler = old_action.sa_handler;
+  unblock_child_signal ();
 }
 
 
diff --git a/src/process.h b/src/process.h
index 9455df18beb..3f86e5f3945 100644
--- a/src/process.h
+++ b/src/process.h
@@ -200,6 +200,8 @@ extern Lisp_Object QCflowcontrol, Qhw, Qsw, QCsummary;
 
 /* Defined in callproc.c.  */
 
+extern void block_child_signal (void);
+extern void unblock_child_signal (void);
 extern void record_kill_process (struct Lisp_Process *);
 
 /* Defined in process.c.  */
diff --git a/src/sysdep.c b/src/sysdep.c
index c2769865b5d..1d3e646d359 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -1901,8 +1901,6 @@ init_signals (bool dumping)
       sigaction (SIGFPE, &action, 0);
     }
 
-  catch_child_signal ();
-
 #ifdef SIGUSR1
   add_user_signal (SIGUSR1, "sigusr1");
 #endif