From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 12 Jan 2007 17:58:08 +0000 (+0000)
Subject: 	* include/atomic.h (atomic_forced_read): New macro.
X-Git-Tag: cvs/fedora-glibc-2_5-20070712T1701~82
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3a055f27811cfe1b76fff6b245e07cdb04cb4a9b;p=thirdparty%2Fglibc.git

	* include/atomic.h (atomic_forced_read): New macro.

	* sysdeps/unix/sysv/linux/pthread_kill.c (pthread_kill): Make sure
	tid isn't reread from pd->tid in between ESRCH test and the syscall.
---

diff --git a/ChangeLog b/ChangeLog
index b4674852e35..f5596363447 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2006-12-21  Ulrich Drepper  <drepper@redhat.com>
+
+	* include/atomic.h (atomic_forced_read): New macro.
+
 2006-12-19  Jakub Jelinek  <jakub@redhat.com>
 
 	* nss/getXXbyYY_r.c: Include atomic.h.
diff --git a/include/atomic.h b/include/atomic.h
index a1598e3850a..d44728b215c 100644
--- a/include/atomic.h
+++ b/include/atomic.h
@@ -324,6 +324,12 @@
 #endif
 
 
+#ifndef atomic_forced_read
+# define atomic_forced_read(x) \
+  ({ __typeof (x) __x; __asm ("" : "=r" (__x) : "0" (x)); __x; })
+#endif
+
+
 #ifndef atomic_delay
 # define atomic_delay() do { /* nothing */ } while (0)
 #endif
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index f96101aa9e1..d8afffea819 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,8 @@
+2006-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	* sysdeps/unix/sysv/linux/pthread_kill.c (pthread_kill): Make sure
+	tid isn't reread from pd->tid in between ESRCH test and the syscall.
+
 2006-09-24  Ulrich Drepper  <drepper@redhat.com>
 
 	[BZ #3251]
diff --git a/nptl/sysdeps/unix/sysv/linux/pthread_kill.c b/nptl/sysdeps/unix/sysv/linux/pthread_kill.c
index 9115d6f40b2..75089365c3e 100644
--- a/nptl/sysdeps/unix/sysv/linux/pthread_kill.c
+++ b/nptl/sysdeps/unix/sysv/linux/pthread_kill.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2004, 2006 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -33,7 +33,15 @@ __pthread_kill (threadid, signo)
   struct pthread *pd = (struct pthread *) threadid;
 
   /* Make sure the descriptor is valid.  */
-  if (INVALID_TD_P (pd))
+  if (DEBUGGING_P && INVALID_TD_P (pd))
+    /* Not a valid thread handle.  */
+    return ESRCH;
+
+  /* Force load of pd->tid into local variable or register.  Otherwise
+     if a thread exits between ESRCH test and tgkill, we might return
+     EINVAL, because pd->tid would be cleared by the kernel.  */
+  pid_t tid = atomic_forced_read (pd->tid);
+  if (__builtin_expect (tid <= 0, 0))
     /* Not a valid thread handle.  */
     return ESRCH;
 
@@ -53,15 +61,15 @@ __pthread_kill (threadid, signo)
   int val;
 #if __ASSUME_TGKILL
   val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid),
-			  pd->tid, signo);
+			  tid, signo);
 #else
 # ifdef __NR_tgkill
   val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid),
-			  pd->tid, signo);
+			  tid, signo);
   if (INTERNAL_SYSCALL_ERROR_P (val, err)
       && INTERNAL_SYSCALL_ERRNO (val, err) == ENOSYS)
 # endif
-    val = INTERNAL_SYSCALL (tkill, err, 2, pd->tid, signo);
+    val = INTERNAL_SYSCALL (tkill, err, 2, tid, signo);
 #endif
 
   return (INTERNAL_SYSCALL_ERROR_P (val, err)