From 47c2a22fd6adcaf3f27b093df49bd97e3fdc16e7 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 10 May 2012 22:16:15 -0400 Subject: [PATCH] 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. --- src/exit/exit.c | 6 ++++-- 1 file 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 #include #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 */ __funcs_on_exit(); -- 2.25.1