From 1cb76b7ca484f9429cf21a24e1cbb4f27ec128f0 Mon Sep 17 00:00:00 2001
From: Nadav Har'El <nyh@cloudius-systems.com>
Date: Wed, 17 Apr 2013 23:30:01 +0300
Subject: [PATCH] Fixed two bugs in pthread implementation
1. pthread_join should allow retval=NULL, in which case the return value is
ignored. We therefore need to use void**, not void*&, otherwise passing NULL
causes pthread_join to crash in a strange way.
2. pthread_join forgot to delete the object allocated in pthread_create
---
libc/pthread.cc | 12 ++++++++----
tests/tst-leak.cc | 17 +++++++++++++++++
2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/libc/pthread.cc b/libc/pthread.cc
index dfd295139..995ba6f4d 100644
--- a/libc/pthread.cc
+++ b/libc/pthread.cc
@@ -35,7 +35,7 @@ namespace pthread_private {
~pthread() { free_stack(_thread.get_stack_info()); }
static pthread* from_libc(pthread_t p);
pthread_t to_libc();
- int join(void*& retval);
+ int join(void** retval);
void* _retval;
// must be initialized last
sched::thread _thread;
@@ -79,10 +79,12 @@ namespace pthread_private {
mmu::unmap(si.begin, si.size);
}
- int pthread::join(void*& retval)
+ int pthread::join(void** retval)
{
_thread.join();
- retval = _retval;
+ if (retval) {
+ *retval = _retval;
+ }
return 0;
}
@@ -124,7 +126,9 @@ int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
int pthread_join(pthread_t thread, void** retval)
{
- return pthread::from_libc(thread)->join(*retval);
+ int ret = pthread::from_libc(thread)->join(retval);
+ delete(pthread::from_libc(thread));
+ return ret;
}
int pthread_key_create(pthread_key_t* key, void (*dtor)(void*))
diff --git a/tests/tst-leak.cc b/tests/tst-leak.cc
index 12356ef8c..87f858853 100644
--- a/tests/tst-leak.cc
+++ b/tests/tst-leak.cc
@@ -1,11 +1,18 @@
#include "sched.hh"
#include "debug.hh"
#include <sys/mman.h>
+#include <pthread.h>
namespace memory {
extern bool tracker_enabled;
}
+static void *donothing(void *arg)
+{
+ debug(".");
+ return NULL;
+}
+
int main(int argc, char **argv)
{
bool save_tracker_enabled = memory::tracker_enabled;
@@ -44,6 +51,16 @@ int main(int argc, char **argv)
t->join();
delete t;
}
+
+ debug("testing leaks in pthread_create");
+ for(int i=0; i<10; i++){
+ pthread_t t;
+ assert(pthread_create(&t, NULL, donothing, NULL) == 0);
+ assert(pthread_join(t, NULL) == 0);
+ }
+ debug("\n");
+
+
debug("leak testing done. Please use 'osv leak show' in gdb to analyze results\n");
memory::tracker_enabled = save_tracker_enabled;
--
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