kc3-lang/libxml2

2023-09-22T13:37:28

globals: Don't use thread-local storage on Darwin It seems that thread-local storage destructors are run before pthread thread-specific data destructors on Darwin, defeating our scheme to use TSD to clean up TLS. Here's an example program that reports a use-after-free when compiled with `-fsanitize=address` on macOS: #include <pthread.h> typedef struct { int v; } my_struct; static _Thread_local my_struct tls; pthread_key_t key; void dtor(void *tsd) { my_struct *s = (my_struct *) tsd; /* * This will crash ASan, apparently because * TLS has already been freed. */ s->v = 1; } void *thread(void *p) { pthread_setspecific(key, &tls); return NULL; } int main(void) { pthread_key_create(&key, dtor); pthread_t handle; pthread_create(&handle, NULL, thread, NULL); pthread_join(handle, NULL); return 0; }