hurdmalloc: Run fork handler as late as possible [BZ #19431]

This is the hurd-specific follow-up for
29d794863cd6e03115d3670707cc873a9965ba92 : hurdmalloc also needs the
same fix

	* hurd/hurdmalloc.c (malloc_fork_prepare): Rename to
	_hurd_malloc_fork_prepare.
	(malloc_fork_parent): Rename to _hurd_malloc_fork_parent.
	(malloc_fork_child): Rename to _hurd_malloc_fork_child.
	(_hurd_fork_prepare_hook): Drop malloc_fork_prepare.
	(_hurd_fork_parent_hook): Drop malloc_fork_parent.
	(_hurd_fork_child_hook): Drop malloc_fork_child.
	* hurd/hurdmalloc.h (_hurd_malloc_fork_prepare,
	_hurd_malloc_fork_parent, _hurd_malloc_fork_child): Add declarations.
	* sysdeps/mach/hurd/fork.c (__fork): Call __malloc_fork_lock_parent
	after locking locks (notably hurd_dtable_lock). Call
	_hurd_malloc_fork_prepare after that. Call _hurd_malloc_fork_parent
	before __malloc_fork_unlock_parent and _hurd_malloc_fork_child before
	__malloc_fork_unlock_child.

4 files changed, 36 insertions, 15 deletions

diff --git a/ChangeLog b/ChangeLog
index e9289778f0..b2add6a3e3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2016-09-22  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	* hurd/hurdmalloc.c (malloc_fork_prepare): Rename to
+	_hurd_malloc_fork_prepare.
+	(malloc_fork_parent): Rename to _hurd_malloc_fork_parent.
+	(malloc_fork_child): Rename to _hurd_malloc_fork_child.
+	(_hurd_fork_prepare_hook): Drop malloc_fork_prepare.
+	(_hurd_fork_parent_hook): Drop malloc_fork_parent.
+	(_hurd_fork_child_hook): Drop malloc_fork_child.
+	* hurd/hurdmalloc.h (_hurd_malloc_fork_prepare,
+	_hurd_malloc_fork_parent, _hurd_malloc_fork_child): Add declarations.
+	* sysdeps/mach/hurd/fork.c (__fork): Call __malloc_fork_lock_parent
+	after locking locks (notably hurd_dtable_lock). Call
+	_hurd_malloc_fork_prepare after that. Call _hurd_malloc_fork_parent
+	before __malloc_fork_unlock_parent and _hurd_malloc_fork_child before
+	__malloc_fork_unlock_child.
+
 2016-09-21  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	* soft-fp/extendhftf2.c: New.
diff --git a/hurd/hurdmalloc.c b/hurd/hurdmalloc.c
index 58c29fa07d..65fb959d84 100644
--- a/hurd/hurdmalloc.c
+++ b/hurd/hurdmalloc.c
@@ -405,8 +405,8 @@ print_malloc_free_list (void)
 }
 #endif	/* DEBUG */
 
-static void
-malloc_fork_prepare(void)
+void
+_hurd_malloc_fork_prepare(void)
 /*
  * Prepare the malloc module for a fork by insuring that no thread is in a
  * malloc critical section.
@@ -419,8 +419,8 @@ malloc_fork_prepare(void)
     }
 }
 
-static void
-malloc_fork_parent(void)
+void
+_hurd_malloc_fork_parent(void)
 /*
  * Called in the parent process after a fork() to resume normal operation.
  */
@@ -432,8 +432,8 @@ malloc_fork_parent(void)
     }
 }
 
-static void
-malloc_fork_child(void)
+void
+_hurd_malloc_fork_child(void)
 /*
  * Called in the child process after a fork() to resume normal operation.
  */
@@ -446,7 +446,4 @@ malloc_fork_child(void)
 }
 
 
-text_set_element (_hurd_fork_prepare_hook, malloc_fork_prepare);
-text_set_element (_hurd_fork_parent_hook, malloc_fork_parent);
-text_set_element (_hurd_fork_child_hook, malloc_fork_child);
 text_set_element (_hurd_preinit_hook, malloc_init);
diff --git a/hurd/hurdmalloc.h b/hurd/hurdmalloc.h
index e11c208a8f..3520ffacd8 100644
--- a/hurd/hurdmalloc.h
+++ b/hurd/hurdmalloc.h
@@ -12,6 +12,10 @@ extern void *_hurd_malloc (size_t);
 extern void *_hurd_realloc (void *, size_t);
 extern void _hurd_free (void *);
 
+extern void _hurd_malloc_fork_prepare (void);
+extern void _hurd_malloc_fork_parent (void);
+extern void _hurd_malloc_fork_child (void);
+
 #define malloc	_hurd_malloc
 #define realloc	_hurd_realloc
 #define free	_hurd_free
diff --git a/sysdeps/mach/hurd/fork.c b/sysdeps/mach/hurd/fork.c
index 9973b1bb9e..9e863a8033 100644
--- a/sysdeps/mach/hurd/fork.c
+++ b/sysdeps/mach/hurd/fork.c
@@ -108,12 +108,6 @@ __fork (void)
       /* Run things that prepare for forking before we create the task.  */
       RUN_HOOK (_hurd_fork_prepare_hook, ());
 
-      /* Acquire malloc locks.  This needs to come last because fork
-	 handlers may use malloc, and the libio list lock has an
-	 indirect malloc dependency as well (via the getdelim
-	 function).  */
-      call_function_static_weak (__malloc_fork_lock_parent);
-
       /* Lock things that want to be locked before we fork.  */
       {
 	void *const *p;
@@ -124,6 +118,13 @@ __fork (void)
       }
       __mutex_lock (&_hurd_siglock);
 
+      /* Acquire malloc locks.  This needs to come last because fork
+	 handlers may use malloc, and the libio list lock has an
+	 indirect malloc dependency as well (via the getdelim
+	 function).  */
+      call_function_static_weak (__malloc_fork_lock_parent);
+      _hurd_malloc_fork_prepare ();
+
       newtask = MACH_PORT_NULL;
       thread = sigthread = MACH_PORT_NULL;
       newproc = MACH_PORT_NULL;
@@ -612,6 +613,7 @@ __fork (void)
 	}
 
       /* Release malloc locks.  */
+      _hurd_malloc_fork_parent ();
       call_function_static_weak (__malloc_fork_unlock_parent);
 
       /* Run things that want to run in the parent to restore it to
@@ -666,6 +668,7 @@ __fork (void)
       __sigemptyset (&_hurdsig_traced);
 
       /* Release malloc locks.  */
+      _hurd_malloc_fork_child ();
       call_function_static_weak (__malloc_fork_unlock_child);
 
       /* Run things that want to run in the child task to set up.  */