diff options
authorRich Felker <>2012-05-10 22:16:15 -0400
committerRich Felker <>2012-05-10 22:16:15 -0400
commit47c2a22fd6adcaf3f27b093df49bd97e3fdc16e7 (patch)
parent7e310e591e61cde57cf3960d6a064a1de2e94e6c (diff)
remove __lock dependency from exit
there's no sense in using a powerful lock in exit, because it will never be unlocked. a thread that arrives at exit while exit is already in progress just needs to hang forever. use the pause syscall for this because it's cheap and easy and universally available.
1 files changed, 4 insertions, 2 deletions
diff --git a/src/exit/exit.c b/src/exit/exit.c
index ae557c09..fc291484 100644
--- a/src/exit/exit.c
+++ b/src/exit/exit.c
@@ -2,6 +2,8 @@
#include <unistd.h>
#include <stdio.h>
#include "libc.h"
+#include "atomic.h"
+#include "syscall.h"
static void dummy()
@@ -13,10 +15,10 @@ weak_alias(dummy, __fflush_on_exit);
void exit(int code)
- static int lock[2];
+ static int lock;
/* If more than one thread calls exit, hang until _Exit ends it all */
- LOCK(lock);
+ while (a_swap(&lock, 1)) __syscall(SYS_pause);
/* Only do atexit & stdio flush if they were actually used */