Fix robust mutex handling after fork

5 files changed, 66 insertions, 15 deletions

diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index e0526fa7b8..c545b079f4 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,13 @@
+2011-06-30  Ulrich Drepper  <drepper@gmail.com>
+
+	* nptl-init.c (__nptl_set_robust): New function.
+	(pthread_functions): Add reference.
+	* npthreadP.h: Declare __nptl_set_robust.
+	* sysdeps/pthread/pthread-functions.h (pthread_functions): Add
+	ptr_set_robust member.
+	* sysdeps/unix/sysv/linux/fork.c: Call set_robust_list syscall in
+	child if threads are used.
+
 2011-06-14  Andreas Jaeger  <aj@suse.de>
 
 	* pthread_rwlock_init.c: Include <string.h> for memset declaration.
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 851bab2bf1..33492c1602 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002-2007, 2008, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2007, 2008, 2009, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -68,6 +68,13 @@ extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
 #endif
 
 #ifdef SHARED
+static
+#else
+extern
+#endif
+void __nptl_set_robust (struct pthread *);
+
+#ifdef SHARED
 static void nptl_freeres (void);
 
 
@@ -130,7 +137,8 @@ static const struct pthread_functions pthread_functions =
     .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
     .ptr__nptl_setxid = __nptl_setxid,
     /* For now only the stack cache needs to be freed.  */
-    .ptr_freeres = nptl_freeres
+    .ptr_freeres = nptl_freeres,
+    .ptr_set_robust = __nptl_set_robust
   };
 # define ptr_pthread_functions &pthread_functions
 #else
@@ -147,7 +155,17 @@ nptl_freeres (void)
   __unwind_freeres ();
   __free_stacks (0);
 }
+
+
+static
 #endif
+void
+__nptl_set_robust (struct pthread *self)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  INTERNAL_SYSCALL (set_robust_list, err, 2, &self->robust_head,
+		    sizeof (struct robust_list_head));
+}
 
 
 /* For asynchronous cancellation we use a signal.  This is the handler.  */
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index 43ca44c829..df4f4d769b 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002-2007, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2007, 2009, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -555,17 +555,20 @@ extern void __pthread_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffe
 
 /* Old cleanup interfaces, still used in libc.so.  */
 extern void _pthread_cleanup_push (struct _pthread_cleanup_buffer *buffer,
-                                   void (*routine) (void *), void *arg);
+				   void (*routine) (void *), void *arg);
 extern void _pthread_cleanup_pop (struct _pthread_cleanup_buffer *buffer,
-                                  int execute);
+				  int execute);
 extern void _pthread_cleanup_push_defer (struct _pthread_cleanup_buffer *buffer,
-                                         void (*routine) (void *), void *arg);
+					 void (*routine) (void *), void *arg);
 extern void _pthread_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer,
-                                          int execute);
+					  int execute);
 
 extern void __nptl_deallocate_tsd (void) attribute_hidden;
 
 extern int __nptl_setxid (struct xid_command *cmdp) attribute_hidden;
+#ifndef SHARED
+extern void __nptl_set_robust (struct pthread *self);
+#endif
 
 extern void __free_stacks (size_t limit) attribute_hidden;
 
diff --git a/nptl/sysdeps/pthread/pthread-functions.h b/nptl/sysdeps/pthread/pthread-functions.h
index 0c404fcbb3..15a4dff142 100644
--- a/nptl/sysdeps/pthread/pthread-functions.h
+++ b/nptl/sysdeps/pthread/pthread-functions.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+/* Copyright (C) 2003, 2004, 2005, 2006, 2007, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
 
@@ -97,6 +97,7 @@ struct pthread_functions
   void (*ptr__nptl_deallocate_tsd) (void);
   int (*ptr__nptl_setxid) (struct xid_command *);
   void (*ptr_freeres) (void);
+  void (*ptr_set_robust) (struct pthread *);
 };
 
 /* Variable in libc.so.  */
diff --git a/nptl/sysdeps/unix/sysv/linux/fork.c b/nptl/sysdeps/unix/sysv/linux/fork.c
index 524d72c587..80fb147788 100644
--- a/nptl/sysdeps/unix/sysv/linux/fork.c
+++ b/nptl/sysdeps/unix/sysv/linux/fork.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2007, 2008 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2007, 2008, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -29,6 +29,7 @@
 #include <ldsodefs.h>
 #include <bits/stdio-lock.h>
 #include <atomic.h>
+#include <pthreadP.h>
 
 
 unsigned long int *__fork_generation_pointer;
@@ -86,8 +87,8 @@ __libc_fork (void)
 	 just go away.  The unloading code works in the order of the
 	 list.
 
-         While executing the registered handlers we are building a
-         list of all the entries so that we can go backward later on.  */
+	 While executing the registered handlers we are building a
+	 list of all the entries so that we can go backward later on.  */
       while (1)
 	{
 	  /* Execute the handler if there is one.  */
@@ -154,6 +155,24 @@ __libc_fork (void)
       GL(dl_cpuclock_offset) = now;
 #endif
 
+#ifdef __NR_set_robust_list
+      /* Initialize the robust mutex list which has been reset during
+	 the fork.  We do not check for errors since if it fails here
+	 it failed at process start as well and noone could have used
+	 robust mutexes.  We also do not have to set
+	 self->robust_head.futex_offset since we inherit the correct
+	 value from the parent.  */
+# ifdef SHARED
+      if (__builtin_expect (__libc_pthread_functions_init, 0))
+	PTHFCT_CALL (ptr_set_robust, (self));
+# else
+      extern __typeof (__nptl_set_robust) __nptl_set_robust
+	__attribute__((weak));
+      if (__builtin_expect (__nptl_set_robust != NULL, 0))
+	__nptl_set_robust (self);
+# endif
+#endif
+
       /* Reset the file list.  These are recursive mutexes.  */
       fresetlockfiles ();
 
@@ -170,10 +189,10 @@ __libc_fork (void)
 	    allp->handler->child_handler ();
 
 	  /* Note that we do not have to wake any possible waiter.
- 	     This is the only thread in the new process.  The count
- 	     may have been bumped up by other threads doing a fork.
- 	     We reset it to 1, to avoid waiting for non-existing
- 	     thread(s) to release the count.  */
+	     This is the only thread in the new process.  The count
+	     may have been bumped up by other threads doing a fork.
+	     We reset it to 1, to avoid waiting for non-existing
+	     thread(s) to release the count.  */
 	  allp->handler->refcntr = 1;
 
 	  /* XXX We could at this point look through the object pool