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authorUlrich Drepper <drepper@redhat.com>2006-12-21 21:50:33 +0000
committerUlrich Drepper <drepper@redhat.com>2006-12-21 21:50:33 +0000
commitfc242bef00206c3bab4117345734ce744f0b7eff (patch)
tree8eaf53937aa9e43d99ea7e520329907b6c313b79 /nptl
parent571511d557820b9ddbc400b7922f8904387ff78c (diff)
downloadglibc-fc242bef00206c3bab4117345734ce744f0b7eff.tar.gz
glibc-fc242bef00206c3bab4117345734ce744f0b7eff.tar.xz
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* include/atomic.h (atomic_forced_read): New macro.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/ChangeLog5
-rw-r--r--nptl/sysdeps/unix/sysv/linux/pthread_kill.c18
2 files changed, 18 insertions, 5 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index 510693de6f..631e20ddbb 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.
+
 2006-12-06  Jakub Jelinek  <jakub@redhat.com>
 
 	* sysdeps/unix/sysv/linux/s390/s390-32/sysdep-cancel.h (PSEUDO): Handle
diff --git a/nptl/sysdeps/unix/sysv/linux/pthread_kill.c b/nptl/sysdeps/unix/sysv/linux/pthread_kill.c
index 9115d6f40b..259c954322 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.  Oherwise
+     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)