Hi,
I think this might be a false positive tsan warning.
Maybe tsan does not see why a desctructor function
can not execute before the last detached thread
terminates.
I created a small test case that receives a warning
which is similar to the one you tried to fix with your
patch:
cat test.c
#include <stdio.h>
#include <pthread.h>
int test;
static void *
t1(void* p)
{
printf("t1\n");
test = 1;
return NULL;
}
static void __attribute__((destructor))
t2 (void)
{
test = 2;
printf("t2\n");
}
int
main()
{
pthread_t t;
pthread_attr_t a;
pthread_attr_init(&a);
pthread_attr_setdetachstate(&a, PTHREAD_CREATE_DETACHED);
pthread_create(&t, &a, t1, NULL);
pthread_attr_destroy(&a);
return 0;
}
gcc -Wall -fsanitize=thread test.c
./a.out
t1
t2
==================
WARNING: ThreadSanitizer: data race (pid=3564)
Write of size 4 at 0x00000060107c by thread T1:
#0 t1 <null> (a.out+0x00000040088e)
Previous write of size 4 at 0x00000060107c by main thread:
#0 t2 <null> (a.out+0x0000004008c6)
#1 <null> <null> (ld-linux-x86-64.so.2+0x0000000108d9)
Location is global 'test' of size 4 at 0x00000060107c
(a.out+0x00000060107c)
Thread T1 (tid=3566, running) created by main thread at:
#0 pthread_create
../../../../gcc-trunk/libsanitizer/tsan/tsan_interceptors.cc:900
(libtsan.so.0+0x00000002914e)
#1 main <null> (a.out+0x00000040092e)
SUMMARY: ThreadSanitizer: data race
(/home/ed/gnu/gcc-test/a.out+0x40088e) in t1
==================
ThreadSanitizer: reported 1 warnings
The warning goes away when the main function explicitly
joins the thread t1.
That is what I do with all my threads whenever possible,
maybe there is a way how you could explicitly join
all running threads?
Bernd.
