X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fkernel.c;h=78978a234a6d8cf53b5011aaf728340462b3206c;hb=a2d808db82a77a9b5133f1aaee2de32d7f990fbc;hp=2cad0b2ab44b8bdd8ece486521e62f6654677e4d;hpb=890d8fe47755c3bad936389cf48ffa141cff41c9;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 2cad0b2ab..78978a234 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -49,17 +49,24 @@ int kernel_add_channel_context(struct ltt_kernel_channel *chan,
 	DBG("Adding context to channel %s", chan->channel->name);
 	ret = kernctl_add_context(chan->fd, &ctx->ctx);
 	if (ret < 0) {
-		if (errno != EEXIST) {
-			PERROR("add context ioctl");
-		} else {
+		switch (errno) {
+		case ENOSYS:
+			/* Exists but not available for this kernel */
+			ret = LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE;
+			goto error;
+		case EEXIST:
 			/* If EEXIST, we just ignore the error */
 			ret = 0;
+			goto end;
+		default:
+			PERROR("add context ioctl");
+			ret = LTTNG_ERR_KERN_CONTEXT_FAIL;
+			goto error;
 		}
-		goto error;
 	}
 
+end:
 	cds_list_add_tail(&ctx->list, &chan->ctx_list);
-
 	return 0;
 
 error:
@@ -659,17 +666,22 @@ error:
  * Open stream of channel, register it to the kernel tracer and add it
  * to the stream list of the channel.
  *
+ * Note: given that the streams may appear in random order wrt CPU
+ * number (e.g. cpu hotplug), the index value of the stream number in
+ * the stream name is not necessarily linked to the CPU number.
+ *
  * Return the number of created stream. Else, a negative value.
  */
 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 {
-	int ret, count = 0;
+	int ret;
 	struct ltt_kernel_stream *lks;
 
 	assert(channel);
 
 	while ((ret = kernctl_create_stream(channel->fd)) >= 0) {
-		lks = trace_kernel_create_stream(channel->channel->name, count);
+		lks = trace_kernel_create_stream(channel->channel->name,
+				channel->stream_count);
 		if (lks == NULL) {
 			ret = close(ret);
 			if (ret) {
@@ -688,13 +700,10 @@ int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 		lks->tracefile_size = channel->channel->attr.tracefile_size;
 		lks->tracefile_count = channel->channel->attr.tracefile_count;
 
-		/* Add stream to channe stream list */
+		/* Add stream to channel stream list */
 		cds_list_add(&lks->list, &channel->stream_list.head);
 		channel->stream_count++;
 
-		/* Increment counter which represent CPU number. */
-		count++;
-
 		DBG("Kernel stream %s created (fd: %d, state: %d)", lks->name, lks->fd,
 				lks->state);
 	}
@@ -829,7 +838,7 @@ int kernel_validate_version(int tracer_fd)
 
 	ret = kernctl_tracer_version(tracer_fd, &version);
 	if (ret < 0) {
-		ERR("Failed at getting the lttng-modules version");
+		ERR("Failed to retrieve the lttng-modules version");
 		goto error;
 	}
 
@@ -841,11 +850,11 @@ int kernel_validate_version(int tracer_fd)
 	}
 	ret = kernctl_tracer_abi_version(tracer_fd, &abi_version);
 	if (ret < 0) {
-		ERR("Failed at getting lttng-modules ABI version");
+		ERR("Failed to retrieve lttng-modules ABI version");
 		goto error;
 	}
 	if (abi_version.major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
-		ERR("Kernel tracer ABI version (%d.%d) is not compatible with expected ABI major version (%d.*)",
+		ERR("Kernel tracer ABI version (%d.%d) does not match the expected ABI major version (%d.*)",
 			abi_version.major, abi_version.minor,
 			LTTNG_MODULES_ABI_MAJOR_VERSION);
 		goto error;
@@ -859,6 +868,7 @@ error_version:
 	ret = -1;
 
 error:
+	ERR("Kernel tracer version check failed; kernel tracing will not be available");
 	return ret;
 }