Fix: check lttng-modules ABI version for RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS support

[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index b836f3d8f5a4c71b408731c3dcdfe1e394e3147e..58b81477b6bd8345bfafc9c603abd9e2686b49dc 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -34,6 +34,7 @@
 #include <lttng/trigger/trigger-internal.h>
 #include <lttng/condition/condition.h>
 #include <lttng/action/action.h>
+#include <lttng/channel.h>
 #include <lttng/channel-internal.h>
 #include <common/string-utils/string-utils.h>
 
@@ -1357,6 +1358,30 @@ int cmd_enable_channel(struct ltt_session *session,
                attr->attr.switch_timer_interval = 0;
        }
 
+       /* Check for feature support */
+       switch (domain->type) {
+       case LTTNG_DOMAIN_KERNEL:
+       {
+               if (kernel_supports_ring_buffer_snapshot_sample_positions(kernel_tracer_fd) != 1) {
+                       /* Sampling position of buffer is not supported */
+                       WARN("Kernel tracer does not support buffer monitoring. "
+                                       "Setting the monitor interval timer to 0 "
+                                       "(disabled) for channel '%s' of session '%s'",
+                                       attr-> name, session->name);
+                       lttng_channel_set_monitor_timer_interval(attr, 0);
+               }
+               break;
+       }
+       case LTTNG_DOMAIN_UST:
+       case LTTNG_DOMAIN_JUL:
+       case LTTNG_DOMAIN_LOG4J:
+       case LTTNG_DOMAIN_PYTHON:
+               break;
+       default:
+               ret = LTTNG_ERR_UNKNOWN_DOMAIN;
+               goto error;
+       }
+
        switch (domain->type) {
        case LTTNG_DOMAIN_KERNEL:
        {