You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
68 lines
1.9 KiB
68 lines
1.9 KiB
// RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
|
|
#include "test.h"
|
|
|
|
// Test case https://github.com/google/sanitizers/issues/494
|
|
// Tsan sees false HB edge on address pointed to by syncp variable.
|
|
// It is false because when acquire is done syncp points to a var in one frame,
|
|
// and during release it points to a var in a different frame.
|
|
// The code is somewhat tricky because it prevents compiler from optimizing
|
|
// our accesses away, structured to not introduce other data races and
|
|
// not introduce other synchronization, and to arrange the vars in different
|
|
// frames to occupy the same address.
|
|
|
|
// The data race CHECK-NOT below actually must be CHECK, because the program
|
|
// does contain the data race on global.
|
|
|
|
// CHECK-NOT: WARNING: ThreadSanitizer: data race
|
|
// CHECK: DONE
|
|
|
|
long global;
|
|
long *syncp;
|
|
long *addr;
|
|
long sink;
|
|
|
|
void *Thread(void *x) {
|
|
while (__atomic_load_n(&syncp, __ATOMIC_ACQUIRE) == 0)
|
|
usleep(1000); // spin wait
|
|
global = 42;
|
|
__atomic_store_n(syncp, 1, __ATOMIC_RELEASE);
|
|
__atomic_store_n(&syncp, 0, __ATOMIC_RELAXED);
|
|
return NULL;
|
|
}
|
|
|
|
void __attribute__((noinline)) foobar() {
|
|
__attribute__((aligned(64))) long s;
|
|
|
|
addr = &s;
|
|
__atomic_store_n(&s, 0, __ATOMIC_RELAXED);
|
|
__atomic_store_n(&syncp, &s, __ATOMIC_RELEASE);
|
|
while (__atomic_load_n(&syncp, __ATOMIC_RELAXED) != 0)
|
|
usleep(1000); // spin wait
|
|
}
|
|
|
|
void __attribute__((noinline)) barfoo() {
|
|
__attribute__((aligned(64))) long s;
|
|
|
|
if (addr != &s) {
|
|
printf("address mismatch addr=%p &s=%p\n", addr, &s);
|
|
exit(1);
|
|
}
|
|
__atomic_store_n(&addr, &s, __ATOMIC_RELAXED);
|
|
__atomic_store_n(&s, 0, __ATOMIC_RELAXED);
|
|
sink = __atomic_load_n(&s, __ATOMIC_ACQUIRE);
|
|
global = 43;
|
|
}
|
|
|
|
int main() {
|
|
pthread_t t;
|
|
pthread_create(&t, 0, Thread, 0);
|
|
foobar();
|
|
barfoo();
|
|
pthread_join(t, 0);
|
|
if (sink != 0)
|
|
exit(1);
|
|
fprintf(stderr, "DONE\n");
|
|
return 0;
|
|
}
|
|
|