Add a rcu noise thread

Author: bernd-edlinger

crypto/threads_pthread.c

@@ -549,6 +549,21 @@ void ossl_synchronize_rcu(CRYPTO_RCU_LOCK *lock)
     }
 }
 
+void ossl_make_noise_rcu(CRYPTO_RCU_LOCK *lock)
+{
+    unsigned int i, j;
+
+    for (j = 0; j < 100; j++) {
+#if defined(__GNUC__) && defined(__ATOMIC_ACQUIRE) && !defined(BROKEN_CLANG_ATOMICS) \
+    && !defined(USE_ATOMIC_FALLBACKS)
+        ATOMIC_ADD_FETCH(&lock->reader_idx, (uint32_t)0, __ATOMIC_RELAXED);
+#endif
+        for (i = 0; i < lock->group_count; i++)
+            ATOMIC_ADD_FETCH(&lock->qp_group[i].users, (uint64_t)0,
+                             __ATOMIC_RELAXED);
+    }
+}
+
 /*
  * Note: This call assumes its made under the protection of
  * ossl_rcu_write_lock

include/internal/rcu.h

@@ -24,6 +24,7 @@ void ossl_rcu_write_lock(CRYPTO_RCU_LOCK *lock);
 void ossl_rcu_write_unlock(CRYPTO_RCU_LOCK *lock);
 void ossl_rcu_read_unlock(CRYPTO_RCU_LOCK *lock);
 void ossl_synchronize_rcu(CRYPTO_RCU_LOCK *lock);
+void ossl_make_noise_rcu(CRYPTO_RCU_LOCK *lock);
 int ossl_rcu_call(CRYPTO_RCU_LOCK *lock, rcu_cb_fn cb, void *data);
 void *ossl_rcu_uptr_deref(void **p);
 void ossl_rcu_assign_uptr(void **p, void **v);

test/threadstest.c

@@ -377,6 +377,7 @@ static void writer2_fn(void)
 {
     int local;
 
+    OSSL_sleep(3000);
     TEST_info("Starting writer2");
     writer_fn(2, &writer2_iterations);
     CRYPTO_atomic_add(&writer2_done, 1, &local, atomiclock);
@@ -429,10 +430,34 @@ static void reader1_fn(void)
 
 static void reader2_fn(void)
 {
+    #ifdef __aarch64__
+    extern unsigned int OPENSSL_armcap_P;
+    if (contention != 0 && (OPENSSL_armcap_P == 0xbd
+                            || OPENSSL_armcap_P == 0x7efd
+                            || OPENSSL_armcap_P == 0x987d))
+        sleep(1000);
+    #endif
+    #ifdef __powerpc64__
+    extern unsigned int OPENSSL_ppccap_P;
+    if (contention != 0 && OPENSSL_ppccap_P == 0xbe)
+        sleep(1000);
+    #endif
     TEST_info("Starting reader 2");
     reader_fn(&reader2_iterations);
 }
 
+static void noise_fn(void)
+{
+    int lw1 = 0;
+    int lw2 = 0;
+
+    while (lw1 != 1 || lw2 != 1) {
+        CRYPTO_atomic_add(&writer1_done, 0, &lw1, atomiclock);
+        CRYPTO_atomic_add(&writer2_done, 0, &lw2, atomiclock);
+        ossl_make_noise_rcu(rcu_lock);
+    }
+}
+
 static thread_t writer1;
 static thread_t writer2;
 static thread_t reader1;
@@ -445,6 +470,7 @@ static int _torture_rcu(void)
     double tottime;
     double avr, avw;
     int rc = 0;
+    thread_t noise;
 
     atomiclock = CRYPTO_THREAD_lock_new();
     if (!TEST_ptr(atomiclock))
@@ -473,6 +499,8 @@ static int _torture_rcu(void)
         || !TEST_true(run_thread(&reader2, reader2_fn))
         || !TEST_true(run_thread(&writer1, writer1_fn))
         || !TEST_true(run_thread(&writer2, writer2_fn))
+        || !TEST_true(run_thread(&noise, noise_fn))
+        || !TEST_true(wait_for_thread(noise))
         || !TEST_true(wait_for_thread(writer1))
         || !TEST_true(wait_for_thread(writer2))
         || !TEST_true(wait_for_thread(reader1))