plan9port

commit 9689b580bdb168b87a20a5e466864337d591acfa
parent 5f4529e351e77e4ab61d258ca3dea69852a1e0ba
Author: rsc <devnull@localhost>
Date:   Wed, 27 Jul 2005 20:25:34 +0000

Try to avoid races in underlying C library
during threadexitsall.

Diffstat:
M
src/libthread/BSD.c
 | 
14
++++++++++++++
M
src/libthread/Linux.c
 | 
14
++++++++++++++

2 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/src/libthread/BSD.c b/src/libthread/BSD.c
@@ -285,6 +285,20 @@ threadexitsall(char *msg)
 	int i, npid, mypid;
 	Proc *p;
 
+	/* 
+	 * Only one guy, ever, gets to run this.
+	 * If two guys do it, inevitably they end up
+	 * tripping over each other in the underlying
+	 * C library exit() implementation, which is
+	 * trying to run the atexit handlers and apparently
+	 * not thread safe.  This has been observed on
+	 * both Linux and OpenBSD.  Sigh.
+	 */
+	{
+		static Lock onelock;
+		lock(&onelock);
+	}
+
 	if(msg == nil)
 		msg = "";
 	mypid = getpid();
diff --git a/src/libthread/Linux.c b/src/libthread/Linux.c
@@ -311,6 +311,20 @@ threadexitsall(char *msg)
 	int i, npid, mypid;
 	Proc *p;
 
+	/* 
+	 * Only one guy, ever, gets to run this.
+	 * If two guys do it, inevitably they end up
+	 * tripping over each other in the underlying
+	 * C library exit() implementation, which is
+	 * trying to run the atexit handlers and apparently
+	 * not thread safe.  This has been observed on
+	 * both Linux and OpenBSD.  Sigh.
+	 */
+	{
+		static Lock onelock;
+		lock(&onelock);
+	}
+
 	if(msg == nil)
 		msg = "";
 	mypid = getpid();