X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=src%2Flib%2Flttng-ust%2Flttng-ust-comm.c;h=0a039feffdb7f8d64085da19118b0fea3a886e42;hb=c246521ddcba1d1d28cfa0482aa500b9122e7264;hp=10883e9675b6374f42bfa38d0b7529eb8cbc05e1;hpb=a987943be74e59e0383b7a5b4b5fa2c47c3ab578;p=lttng-ust.git

diff --git a/src/lib/lttng-ust/lttng-ust-comm.c b/src/lib/lttng-ust/lttng-ust-comm.c
index 10883e96..0a039fef 100644
--- a/src/lib/lttng-ust/lttng-ust-comm.c
+++ b/src/lib/lttng-ust/lttng-ust-comm.c
@@ -387,7 +387,7 @@ const char *get_lttng_home_dir(void)
  * Force a read (imply TLS allocation for dlopen) of TLS variables.
  */
 static
-void lttng_nest_count_alloc_tls(void)
+void lttng_ust_nest_count_alloc_tls(void)
 {
 	asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count)));
 }
@@ -402,26 +402,26 @@ void lttng_ust_mutex_nest_alloc_tls(void)
  * Allocate lttng-ust urcu TLS.
  */
 static
-void lttng_lttng_ust_urcu_alloc_tls(void)
+void lttng_ust_urcu_alloc_tls(void)
 {
 	(void) lttng_ust_urcu_read_ongoing();
 }
 
-void lttng_ust_alloc_tls(void)
+void lttng_ust_common_init_thread(int flags)
 {
-	lttng_lttng_ust_urcu_alloc_tls();
+	lttng_ust_urcu_alloc_tls();
 	lttng_ringbuffer_alloc_tls();
-	lttng_vtid_alloc_tls();
-	lttng_nest_count_alloc_tls();
-	lttng_procname_alloc_tls();
+	lttng_ust_vtid_init_thread(flags);
+	lttng_ust_nest_count_alloc_tls();
+	lttng_ust_procname_init_thread(flags);
 	lttng_ust_mutex_nest_alloc_tls();
-	lttng_ust_perf_counter_alloc_tls();
+	lttng_ust_perf_counter_init_thread(flags);
 	lttng_ust_common_alloc_tls();
-	lttng_cgroup_ns_alloc_tls();
-	lttng_ipc_ns_alloc_tls();
-	lttng_net_ns_alloc_tls();
-	lttng_time_ns_alloc_tls();
-	lttng_uts_ns_alloc_tls();
+	lttng_ust_cgroup_ns_init_thread(flags);
+	lttng_ust_ipc_ns_init_thread(flags);
+	lttng_ust_net_ns_init_thread(flags);
+	lttng_ust_time_ns_init_thread(flags);
+	lttng_ust_uts_ns_init_thread(flags);
 	lttng_ust_ring_buffer_client_discard_alloc_tls();
 	lttng_ust_ring_buffer_client_discard_rt_alloc_tls();
 	lttng_ust_ring_buffer_client_overwrite_alloc_tls();
@@ -446,7 +446,7 @@ void lttng_ust_init_thread(void)
 	 * ensure those are initialized before a signal handler nesting over
 	 * this thread attempts to use them.
 	 */
-	lttng_ust_alloc_tls();
+	lttng_ust_common_init_thread(LTTNG_UST_INIT_THREAD_MASK);
 }
 
 int lttng_get_notify_socket(void *owner)
@@ -1757,18 +1757,25 @@ void wait_for_sessiond(struct sock_info *sock_info)
 
 	DBG("Waiting for %s apps sessiond", sock_info->name);
 	/* Wait for futex wakeup */
-	if (uatomic_read((int32_t *) sock_info->wait_shm_mmap))
-		goto end_wait;
-
-	while (lttng_ust_futex_async((int32_t *) sock_info->wait_shm_mmap,
-			FUTEX_WAIT, 0, NULL, NULL, 0)) {
+	while (!uatomic_read((int32_t *) sock_info->wait_shm_mmap)) {
+		if (!lttng_ust_futex_async((int32_t *) sock_info->wait_shm_mmap, FUTEX_WAIT, 0, NULL, NULL, 0)) {
+			/*
+			 * Prior queued wakeups queued by unrelated code
+			 * using the same address can cause futex wait to
+			 * return 0 even through the futex value is still
+			 * 0 (spurious wakeups). Check the value again
+			 * in user-space to validate whether it really
+			 * differs from 0.
+			 */
+			continue;
+		}
 		switch (errno) {
-		case EWOULDBLOCK:
+		case EAGAIN:
 			/* Value already changed. */
 			goto end_wait;
 		case EINTR:
 			/* Retry if interrupted by signal. */
-			break;	/* Get out of switch. */
+			break;	/* Get out of switch. Check again. */
 		case EFAULT:
 			wait_poll_fallback = 1;
 			DBG(
@@ -1808,7 +1815,7 @@ void *ust_listener_thread(void *arg)
 	int sock, ret, prev_connect_failed = 0, has_waited = 0, fd;
 	long timeout;
 
-	lttng_ust_alloc_tls();
+	lttng_ust_common_init_thread(0);
 	/*
 	 * If available, add '-ust' to the end of this thread's
 	 * process name
@@ -2176,7 +2183,7 @@ void lttng_ust_ctor(void)
 	 * to be the dynamic linker mutex) and ust_lock, taken within
 	 * the ust lock.
 	 */
-	lttng_ust_alloc_tls();
+	lttng_ust_common_init_thread(0);
 
 	lttng_ust_loaded = 1;
 
@@ -2490,7 +2497,7 @@ void lttng_ust_before_fork(sigset_t *save_sigset)
 	int ret;
 
 	/* Allocate lttng-ust TLS. */
-	lttng_ust_alloc_tls();
+	lttng_ust_common_init_thread(0);
 
 	if (URCU_TLS(lttng_ust_nest_count))
 		return;