X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=cc9b6b5e1e8706a1b941de1b0d09ea37dddaffd3;hb=2315088b93f925c5cccee865ccb8f6bc542e52dc;hp=6eb4a892f7bf7d343ec3d77b8e9d6ab0cea38b33;hpb=c0bbbd5af5c91c2f7b7b23fcc860b3e48754c059;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 6eb4a892..cc9b6b5e 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -20,6 +20,7 @@
  */
 
 #define _LGPL_SOURCE
+#define _GNU_SOURCE
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/mman.h>
@@ -34,7 +35,6 @@
 #include <time.h>
 #include <assert.h>
 #include <signal.h>
-#include <dlfcn.h>
 #include <urcu/uatomic.h>
 #include <urcu/futex.h>
 #include <urcu/compiler.h>
@@ -52,7 +52,10 @@
 #include "lttng-tracer-core.h"
 #include "compat.h"
 #include "../libringbuffer/tlsfixup.h"
-#include "lttng-ust-baddr.h"
+#include "lttng-ust-statedump.h"
+#include "clock.h"
+#include "../libringbuffer/getcpu.h"
+#include "getenv.h"
 
 /*
  * Has lttng ust comm constructor been called ?
@@ -68,9 +71,21 @@ static int initialized;
  * probe registration.
  *
  * ust_exit_mutex must never nest in ust_mutex.
+ *
+ * ust_fork_mutex must never nest in ust_mutex.
+ *
+ * ust_mutex_nest is a per-thread nesting counter, allowing the perf
+ * counter lazy initialization called by events within the statedump,
+ * which traces while the ust_mutex is held.
+ *
+ * ust_lock nests within the dynamic loader lock (within glibc) because
+ * it is taken within the library constructor.
  */
 static pthread_mutex_t ust_mutex = PTHREAD_MUTEX_INITIALIZER;
 
+/* Allow nesting the ust_mutex within the same thread. */
+static DEFINE_URCU_TLS(int, ust_mutex_nest);
+
 /*
  * ust_exit_mutex protects thread_active variable wrt thread exit. It
  * cannot be done by ust_mutex because pthread_cancel(), which takes an
@@ -80,16 +95,45 @@ static pthread_mutex_t ust_mutex = PTHREAD_MUTEX_INITIALIZER;
  */
 static pthread_mutex_t ust_exit_mutex = PTHREAD_MUTEX_INITIALIZER;
 
+/*
+ * ust_fork_mutex protects base address statedump tracing against forks. It
+ * prevents the dynamic loader lock to be taken (by base address statedump
+ * tracing) while a fork is happening, thus preventing deadlock issues with
+ * the dynamic loader lock.
+ */
+static pthread_mutex_t ust_fork_mutex = PTHREAD_MUTEX_INITIALIZER;
+
 /* Should the ust comm thread quit ? */
 static int lttng_ust_comm_should_quit;
 
 /*
- * Return 0 on success, -1 if should quilt.
+ * Return 0 on success, -1 if should quit.
  * The lock is taken in both cases.
+ * Signal-safe.
  */
 int ust_lock(void)
 {
-	pthread_mutex_lock(&ust_mutex);
+	sigset_t sig_all_blocked, orig_mask;
+	int ret, oldstate;
+
+	ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
+	if (ret) {
+		ERR("pthread_setcancelstate: %s", strerror(ret));
+	}
+	if (oldstate != PTHREAD_CANCEL_ENABLE) {
+		ERR("pthread_setcancelstate: unexpected oldstate");
+	}
+	sigfillset(&sig_all_blocked);
+	ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
+	if (ret) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
+	if (!URCU_TLS(ust_mutex_nest)++)
+		pthread_mutex_lock(&ust_mutex);
+	ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
+	if (ret) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
 	if (lttng_ust_comm_should_quit) {
 		return -1;
 	} else {
@@ -101,15 +145,59 @@ int ust_lock(void)
  * ust_lock_nocheck() can be used in constructors/destructors, because
  * they are already nested within the dynamic loader lock, and therefore
  * have exclusive access against execution of liblttng-ust destructor.
+ * Signal-safe.
  */
 void ust_lock_nocheck(void)
 {
-	pthread_mutex_lock(&ust_mutex);
+	sigset_t sig_all_blocked, orig_mask;
+	int ret, oldstate;
+
+	ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
+	if (ret) {
+		ERR("pthread_setcancelstate: %s", strerror(ret));
+	}
+	if (oldstate != PTHREAD_CANCEL_ENABLE) {
+		ERR("pthread_setcancelstate: unexpected oldstate");
+	}
+	sigfillset(&sig_all_blocked);
+	ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
+	if (ret) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
+	if (!URCU_TLS(ust_mutex_nest)++)
+		pthread_mutex_lock(&ust_mutex);
+	ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
+	if (ret) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
 }
 
+/*
+ * Signal-safe.
+ */
 void ust_unlock(void)
 {
-	pthread_mutex_unlock(&ust_mutex);
+	sigset_t sig_all_blocked, orig_mask;
+	int ret, oldstate;
+
+	sigfillset(&sig_all_blocked);
+	ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
+	if (ret) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
+	if (!--URCU_TLS(ust_mutex_nest))
+		pthread_mutex_unlock(&ust_mutex);
+	ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
+	if (ret) {
+		ERR("pthread_sigmask: %s", strerror(ret));
+	}
+	ret = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
+	if (ret) {
+		ERR("pthread_setcancelstate: %s", strerror(ret));
+	}
+	if (oldstate != PTHREAD_CANCEL_DISABLE) {
+		ERR("pthread_setcancelstate: unexpected oldstate");
+	}
 }
 
 /*
@@ -241,6 +329,24 @@ extern void lttng_ring_buffer_client_discard_exit(void);
 extern void lttng_ring_buffer_client_discard_rt_exit(void);
 extern void lttng_ring_buffer_metadata_client_exit(void);
 
+ssize_t lttng_ust_read(int fd, void *buf, size_t len)
+{
+	ssize_t ret;
+	size_t copied = 0, to_copy = len;
+
+	do {
+		ret = read(fd, buf + copied, to_copy);
+		if (ret > 0) {
+			copied += ret;
+			to_copy -= ret;
+		}
+	} while ((ret > 0 && to_copy > 0)
+		|| (ret < 0 && errno == EINTR));
+	if (ret > 0) {
+		ret = copied;
+	}
+	return ret;
+}
 /*
  * Returns the HOME directory path. Caller MUST NOT free(3) the returned
  * pointer.
@@ -250,11 +356,11 @@ const char *get_lttng_home_dir(void)
 {
        const char *val;
 
-       val = (const char *) getenv("LTTNG_HOME");
+       val = (const char *) lttng_secure_getenv("LTTNG_HOME");
        if (val != NULL) {
                return val;
        }
-       return (const char *) getenv("HOME");
+       return (const char *) lttng_secure_getenv("HOME");
 }
 
 /*
@@ -266,6 +372,22 @@ void lttng_fixup_nest_count_tls(void)
 	asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count)));
 }
 
+static
+void lttng_fixup_ust_mutex_nest_tls(void)
+{
+	asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest)));
+}
+
+/*
+ * Fixup urcu bp TLS.
+ */
+static
+void lttng_fixup_urcu_bp_tls(void)
+{
+	rcu_read_lock();
+	rcu_read_unlock();
+}
+
 int lttng_get_notify_socket(void *owner)
 {
 	struct sock_info *info = owner;
@@ -320,7 +442,7 @@ int setup_local_apps(void)
 
 /*
  * Get notify_sock timeout, in ms.
- * -1: don't wait. 0: wait forever. >0: timeout, in ms.
+ * -1: wait forever. 0: don't wait. >0: timeout, in ms.
  */
 static
 long get_timeout(void)
@@ -333,6 +455,9 @@ long get_timeout(void)
 	}
 	if (str_timeout)
 		constructor_delay_ms = strtol(str_timeout, NULL, 10);
+	/* All negative values are considered as "-1". */
+	if (constructor_delay_ms < -1)
+		constructor_delay_ms = -1;
 	return constructor_delay_ms;
 }
 
@@ -343,7 +468,7 @@ long get_notify_sock_timeout(void)
 }
 
 /*
- * Return values: -1: don't wait. 0: wait forever. 1: timeout wait.
+ * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
  */
 static
 int get_constructor_timeout(struct timespec *constructor_timeout)
@@ -366,7 +491,8 @@ int get_constructor_timeout(struct timespec *constructor_timeout)
 	 */
 	ret = clock_gettime(CLOCK_REALTIME, constructor_timeout);
 	if (ret) {
-		return -1;
+		/* Don't wait. */
+		return 0;
 	}
 	constructor_timeout->tv_sec += constructor_delay_ms / 1000UL;
 	constructor_timeout->tv_nsec +=
@@ -375,6 +501,7 @@ int get_constructor_timeout(struct timespec *constructor_timeout)
 		constructor_timeout->tv_sec++;
 		constructor_timeout->tv_nsec -= 1000000000UL;
 	}
+	/* Timeout wait (constructor_delay_ms). */
 	return 1;
 }
 
@@ -450,7 +577,9 @@ void handle_pending_statedump(struct sock_info *sock_info)
 
 	if (ctor_passed && sock_info->statedump_pending) {
 		sock_info->statedump_pending = 0;
+		pthread_mutex_lock(&ust_fork_mutex);
 		lttng_handle_pending_statedump(sock_info);
+		pthread_mutex_unlock(&ust_fork_mutex);
 	}
 }
 
@@ -462,19 +591,20 @@ int handle_message(struct sock_info *sock_info,
 	const struct lttng_ust_objd_ops *ops;
 	struct ustcomm_ust_reply lur;
 	union ust_args args;
+	char ctxstr[LTTNG_UST_SYM_NAME_LEN];	/* App context string. */
 	ssize_t len;
 
 	memset(&lur, 0, sizeof(lur));
 
 	if (ust_lock()) {
 		ret = -LTTNG_UST_ERR_EXITING;
-		goto end;
+		goto error;
 	}
 
 	ops = objd_ops(lum->handle);
 	if (!ops) {
 		ret = -ENOENT;
-		goto end;
+		goto error;
 	}
 
 	switch (lum->cmd) {
@@ -535,12 +665,12 @@ int handle_message(struct sock_info *sock_info,
 				}
 				ret = len;
 				free(bytecode);
-				goto end;
+				goto error;
 			} else {
 				DBG("incorrect filter data message size: %zd", len);
 				ret = -EINVAL;
 				free(bytecode);
-				goto end;
+				goto error;
 			}
 		}
 		bytecode->bc.len = lum->u.filter.data_size;
@@ -600,12 +730,12 @@ int handle_message(struct sock_info *sock_info,
 				}
 				ret = len;
 				free(node);
-				goto end;
+				goto error;
 			} else {
 				DBG("Incorrect exclusion data message size: %zd", len);
 				ret = -EINVAL;
 				free(node);
-				goto end;
+				goto error;
 			}
 		}
 		if (ops->cmd) {
@@ -646,11 +776,11 @@ int handle_message(struct sock_info *sock_info,
 					goto error;
 				}
 				ret = len;
-				goto end;
+				goto error;
 			} else {
 				DBG("incorrect channel data message size: %zd", len);
 				ret = -EINVAL;
-				goto end;
+				goto error;
 			}
 		}
 		args.channel.chan_data = chan_data;
@@ -671,7 +801,7 @@ int handle_message(struct sock_info *sock_info,
 			&args.stream.shm_fd,
 			&args.stream.wakeup_fd);
 		if (ret) {
-			goto end;
+			goto error;
 		}
 		if (ops->cmd)
 			ret = ops->cmd(lum->handle, lum->cmd,
@@ -681,6 +811,64 @@ int handle_message(struct sock_info *sock_info,
 			ret = -ENOSYS;
 		break;
 	}
+	case LTTNG_UST_CONTEXT:
+		switch (lum->u.context.ctx) {
+		case LTTNG_UST_CONTEXT_APP_CONTEXT:
+		{
+			char *p;
+			size_t ctxlen, recvlen;
+
+			ctxlen = strlen("$app.") + lum->u.context.u.app_ctx.provider_name_len - 1
+					+ strlen(":") + lum->u.context.u.app_ctx.ctx_name_len;
+			if (ctxlen >= LTTNG_UST_SYM_NAME_LEN) {
+				ERR("Application context string length size is too large: %zu bytes",
+					ctxlen);
+				ret = -EINVAL;
+				goto error;
+			}
+			strcpy(ctxstr, "$app.");
+			p = &ctxstr[strlen("$app.")];
+			recvlen = ctxlen - strlen("$app.");
+			len = ustcomm_recv_unix_sock(sock, p, recvlen);
+			switch (len) {
+			case 0:	/* orderly shutdown */
+				ret = 0;
+				goto error;
+			default:
+				if (len == recvlen) {
+					DBG("app context data received");
+					break;
+				} else if (len < 0) {
+					DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
+					if (len == -ECONNRESET) {
+						ERR("%s remote end closed connection", sock_info->name);
+						ret = len;
+						goto error;
+					}
+					ret = len;
+					goto error;
+				} else {
+					DBG("incorrect app context data message size: %zd", len);
+					ret = -EINVAL;
+					goto error;
+				}
+			}
+			/* Put : between provider and ctxname. */
+			p[lum->u.context.u.app_ctx.provider_name_len - 1] = ':';
+			args.app_context.ctxname = ctxstr;
+			break;
+		}
+		default:
+			break;
+		}
+		if (ops->cmd) {
+			ret = ops->cmd(lum->handle, lum->cmd,
+					(unsigned long) &lum->u,
+					&args, sock_info);
+		} else {
+			ret = -ENOSYS;
+		}
+		break;
 	default:
 		if (ops->cmd)
 			ret = ops->cmd(lum->handle, lum->cmd,
@@ -691,7 +879,6 @@ int handle_message(struct sock_info *sock_info,
 		break;
 	}
 
-end:
 	lur.handle = lum->handle;
 	lur.cmd = lum->cmd;
 	lur.ret_val = ret;
@@ -820,9 +1007,19 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting)
 		sock_info->notify_socket = -1;
 	}
 	if (sock_info->wait_shm_mmap) {
-		ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE));
-		if (ret) {
-			ERR("Error unmapping wait shm");
+		long page_size;
+
+		page_size = sysconf(_SC_PAGE_SIZE);
+		if (page_size <= 0) {
+			if (!page_size) {
+				errno = EINVAL;
+			}
+			PERROR("Error in sysconf(_SC_PAGE_SIZE)");
+		} else {
+			ret = munmap(sock_info->wait_shm_mmap, page_size);
+			if (ret) {
+				ERR("Error unmapping wait shm");
+			}
 		}
 		sock_info->wait_shm_mmap = NULL;
 	}
@@ -995,15 +1192,24 @@ error_close:
 static
 char *get_map_shm(struct sock_info *sock_info)
 {
-	size_t mmap_size = sysconf(_SC_PAGE_SIZE);
+	long page_size;
 	int wait_shm_fd, ret;
 	char *wait_shm_mmap;
 
-	wait_shm_fd = get_wait_shm(sock_info, mmap_size);
+	page_size = sysconf(_SC_PAGE_SIZE);
+	if (page_size <= 0) {
+		if (!page_size) {
+			errno = EINVAL;
+		}
+		PERROR("Error in sysconf(_SC_PAGE_SIZE)");
+		goto error;
+	}
+
+	wait_shm_fd = get_wait_shm(sock_info, page_size);
 	if (wait_shm_fd < 0) {
 		goto error;
 	}
-	wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ,
+	wait_shm_mmap = mmap(NULL, page_size, PROT_READ,
 		  MAP_SHARED, wait_shm_fd, 0);
 	/* close shm fd immediately after taking the mmap reference */
 	ret = close(wait_shm_fd);
@@ -1023,8 +1229,6 @@ error:
 static
 void wait_for_sessiond(struct sock_info *sock_info)
 {
-	int ret;
-
 	if (ust_lock()) {
 		goto quit;
 	}
@@ -1040,23 +1244,32 @@ 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) == 0) {
-		ret = futex_async((int32_t *) sock_info->wait_shm_mmap,
-			FUTEX_WAIT, 0, NULL, NULL, 0);
-		if (ret < 0) {
-			if (errno == EFAULT) {
-				wait_poll_fallback = 1;
-				DBG(
+	if (uatomic_read((int32_t *) sock_info->wait_shm_mmap))
+		goto end_wait;
+
+	while (futex_async((int32_t *) sock_info->wait_shm_mmap,
+			FUTEX_WAIT, 0, NULL, NULL, 0)) {
+		switch (errno) {
+		case EWOULDBLOCK:
+			/* Value already changed. */
+			goto end_wait;
+		case EINTR:
+			/* Retry if interrupted by signal. */
+			break;	/* Get out of switch. */
+		case EFAULT:
+			wait_poll_fallback = 1;
+			DBG(
 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
 "Please upgrade your kernel "
 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
 "mainline). LTTng-UST will use polling mode fallback.");
-				if (ust_debug())
-					PERROR("futex");
-			}
+			if (ust_debug())
+				PERROR("futex");
+			goto end_wait;
 		}
 	}
+end_wait:
 	return;
 
 quit:
@@ -1082,6 +1295,15 @@ void *ust_listener_thread(void *arg)
 	int sock, ret, prev_connect_failed = 0, has_waited = 0;
 	long timeout;
 
+	/*
+	 * If available, add '-ust' to the end of this thread's
+	 * process name
+	 */
+	ret = lttng_ust_setustprocname();
+	if (ret) {
+		ERR("Unable to set UST process name");
+	}
+
 	/* Restart trying to connect to the session daemon */
 restart:
 	if (prev_connect_failed) {
@@ -1095,8 +1317,9 @@ restart:
 			 * deals with a killed or broken session daemon.
 			 */
 			sleep(5);
+		} else {
+			has_waited = 1;
 		}
-		has_waited = 1;
 		prev_connect_failed = 0;
 	}
 
@@ -1275,7 +1498,13 @@ restart:
 			print_cmd(lum.cmd, lum.handle);
 			ret = handle_message(sock_info, sock, &lum);
 			if (ret) {
-				ERR("Error handling message for %s socket", sock_info->name);
+				ERR("Error handling message for %s socket",
+					sock_info->name);
+				/*
+				 * Close socket if protocol error is
+				 * detected.
+				 */
+				goto end;
 			}
 			continue;
 		default:
@@ -1310,6 +1539,21 @@ quit:
 	return NULL;
 }
 
+/*
+ * Weak symbol to call when the ust malloc wrapper is not loaded.
+ */
+__attribute__((weak))
+void lttng_ust_malloc_wrapper_init(void)
+{
+}
+
+static
+void init_ust_env(void)
+{
+	if (putenv("LTTNG_UST_LOADED=1"))
+		DBG("Error setting LTTNG_UST_LOADED environment variable");
+}
+
 /*
  * sessiond monitoring thread: monitor presence of global and per-user
  * sessiond by polling the application common named pipe.
@@ -1330,10 +1574,14 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	 * to be the dynamic linker mutex) and ust_lock, taken within
 	 * the ust lock.
 	 */
+	lttng_fixup_urcu_bp_tls();
 	lttng_fixup_ringbuffer_tls();
 	lttng_fixup_vtid_tls();
 	lttng_fixup_nest_count_tls();
 	lttng_fixup_procname_tls();
+	lttng_fixup_ust_mutex_nest_tls();
+
+	init_ust_env();
 
 	/*
 	 * We want precise control over the order in which we construct
@@ -1343,17 +1591,26 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	 */
 	init_usterr();
 	init_tracepoint();
+	lttng_ust_clock_init();
+	lttng_ust_getcpu_init();
+	lttng_ust_statedump_init();
 	lttng_ring_buffer_metadata_client_init();
 	lttng_ring_buffer_client_overwrite_init();
 	lttng_ring_buffer_client_overwrite_rt_init();
 	lttng_ring_buffer_client_discard_init();
 	lttng_ring_buffer_client_discard_rt_init();
-	lttng_context_init();
+	lttng_perf_counter_init();
+	/*
+	 * Invoke ust malloc wrapper init before starting other threads.
+	 */
+	lttng_ust_malloc_wrapper_init();
 
 	timeout_mode = get_constructor_timeout(&constructor_timeout);
 
 	ret = sem_init(&constructor_wait, 0, 0);
-	assert(!ret);
+	if (ret) {
+		PERROR("sem_init");
+	}
 
 	ret = setup_local_apps();
 	if (ret) {
@@ -1418,17 +1675,34 @@ void __attribute__((constructor)) lttng_ust_init(void)
 			ret = sem_timedwait(&constructor_wait,
 					&constructor_timeout);
 		} while (ret < 0 && errno == EINTR);
-		if (ret < 0 && errno == ETIMEDOUT) {
-			ERR("Timed out waiting for lttng-sessiond");
-		} else {
-			assert(!ret);
+		if (ret < 0) {
+			switch (errno) {
+			case ETIMEDOUT:
+				ERR("Timed out waiting for lttng-sessiond");
+				break;
+			case EINVAL:
+				PERROR("sem_timedwait");
+				break;
+			default:
+				ERR("Unexpected error \"%s\" returned by sem_timedwait",
+					strerror(errno));
+			}
 		}
 		break;
 	case -1:/* wait forever */
 		do {
 			ret = sem_wait(&constructor_wait);
 		} while (ret < 0 && errno == EINTR);
-		assert(!ret);
+		if (ret < 0) {
+			switch (errno) {
+			case EINVAL:
+				PERROR("sem_wait");
+				break;
+			default:
+				ERR("Unexpected error \"%s\" returned by sem_wait",
+					strerror(errno));
+			}
+		}
 		break;
 	case 0:	/* no timeout */
 		break;
@@ -1439,9 +1713,7 @@ static
 void lttng_ust_cleanup(int exiting)
 {
 	cleanup_sock_info(&global_apps, exiting);
-	if (local_apps.allowed) {
-		cleanup_sock_info(&local_apps, exiting);
-	}
+	cleanup_sock_info(&local_apps, exiting);
 	/*
 	 * The teardown in this function all affect data structures
 	 * accessed under the UST lock by the listener thread. This
@@ -1451,12 +1723,13 @@ void lttng_ust_cleanup(int exiting)
 	 */
 	lttng_ust_abi_exit();
 	lttng_ust_events_exit();
-	lttng_context_exit();
+	lttng_perf_counter_exit();
 	lttng_ring_buffer_client_discard_rt_exit();
 	lttng_ring_buffer_client_discard_exit();
 	lttng_ring_buffer_client_overwrite_rt_exit();
 	lttng_ring_buffer_client_overwrite_exit();
 	lttng_ring_buffer_metadata_client_exit();
+	lttng_ust_statedump_destroy();
 	exit_tracepoint();
 	if (!exiting) {
 		/* Reinitialize values for fork */
@@ -1544,6 +1817,9 @@ void ust_before_fork(sigset_t *save_sigset)
 	if (ret == -1) {
 		PERROR("sigprocmask");
 	}
+
+	pthread_mutex_lock(&ust_fork_mutex);
+
 	ust_lock_nocheck();
 	rcu_bp_before_fork();
 }
@@ -1554,6 +1830,9 @@ static void ust_after_fork_common(sigset_t *restore_sigset)
 
 	DBG("process %d", getpid());
 	ust_unlock();
+
+	pthread_mutex_unlock(&ust_fork_mutex);
+
 	/* Restore signals */
 	ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL);
 	if (ret == -1) {