Fix: ignore error when loading optional kmod

This commit also improves the accuracy of debug messages: a module is
not "successfully" loaded when it's optional and actually not loaded.

Fixes: #837
Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>

diff --git a/src/bin/lttng-sessiond/modprobe.c b/src/bin/lttng-sessiond/modprobe.c
index d329bb9514905570a1c3a25c36c5a9672d4bf353..a28356b423129958728f0ee66a4029163214a965 100644 (file)
--- a/src/bin/lttng-sessiond/modprobe.c
+++ b/src/bin/lttng-sessiond/modprobe.c
@@ -209,8 +209,16 @@ static int modprobe_lttng(struct kern_modules_param *modules,
 
                ret = kmod_module_probe_insert_module(mod, KMOD_PROBE_IGNORE_LOADED,
                                NULL, NULL, NULL, NULL);
-               if (required && ret < 0) {
-                       ERR("Unable to load module %s", modules[i].name);
+               if (ret < 0) {
+                       if (required) {
+                               ERR("Unable to load required module %s",
+                                               modules[i].name);
+                               goto error;
+                       } else {
+                               DBG("Unable to load optional module %s; continuing",
+                                               modules[i].name);
+                               ret = 0;
+                       }
                } else {
                        DBG("Modprobe successfully %s", modules[i].name);
                }
@@ -245,10 +253,25 @@ static int modprobe_lttng(struct kern_modules_param *modules,
                modprobe[sizeof(modprobe) - 1] = '\0';
                ret = system(modprobe);
                if (ret == -1) {
-                       ERR("Unable to launch modprobe for module %s",
-                                       modules[i].name);
-               } else if (required && WEXITSTATUS(ret) != 0) {
-                       ERR("Unable to load module %s", modules[i].name);
+                       if (required) {
+                               ERR("Unable to launch modprobe for required module %s",
+                                               modules[i].name);
+                               goto error;
+                       } else {
+                               DBG("Unable to launch modprobe for optional module %s; continuing",
+                                               modules[i].name);
+                               ret = 0;
+                       }
+               } else if (WEXITSTATUS(ret) != 0) {
+                       if (required) {
+                               ERR("Unable to load required module %s",
+                                               modules[i].name);
+                               goto error;
+                       } else {
+                               DBG("Unable to load optional module %s; continuing",
+                                               modules[i].name);
+                               ret = 0;
+                       }
                } else {
                        DBG("Modprobe successfully %s", modules[i].name);
                }