lttng-probes: Warn of event's and provider's name for mismatch

We have experience serveral cases of such mismatches. To make it easier to
debug, let's warn users of the event's and the provide's name.

Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I455bf92f9f735f890753c9103d22986e56e02e5d

diff --git a/src/lttng-probes.c b/src/lttng-probes.c
index aba7ada5767faba1db997e748b5569dd304bb456..8cf1a75db7672182a6dedf540bb486a27f699a2d 100644 (file)
--- a/src/lttng-probes.c
+++ b/src/lttng-probes.c
@@ -41,24 +41,31 @@ EXPORT_PER_CPU_SYMBOL_GPL(lttng_dynamic_len_stack);
 static
 int check_event_provider(struct lttng_kernel_probe_desc *desc)
 {
-       int i;
+       int i, mismatch = 0;
        size_t provider_name_len;
 
        provider_name_len = strnlen(desc->provider_name,
                                LTTNG_KERNEL_ABI_SYM_NAME_LEN - 1);
        for (i = 0; i < desc->nr_events; i++) {
-               if (strncmp(desc->event_desc[i]->event_name,
-                               desc->provider_name,
-                               provider_name_len))
-                       return 0;       /* provider mismatch */
                /*
-                * The event needs to contain at least provider name + _ +
+                * The event name needs to start with provider name + _ +
                 * one or more letter.
                 */
-               if (strlen(desc->event_desc[i]->event_name) <= provider_name_len + 1)
-                       return 0;       /* provider mismatch */
-               if (desc->event_desc[i]->event_name[provider_name_len] != '_')
-                       return 0;       /* provider mismatch */
+               if (strncmp(desc->event_desc[i]->event_name, desc->provider_name, provider_name_len))
+                       mismatch = 1;
+               else if (strlen(desc->event_desc[i]->event_name) <= provider_name_len + 1)
+                       mismatch = 1;
+               else if (desc->event_desc[i]->event_name[provider_name_len] != '_')
+                       mismatch = 1;
+
+               if (mismatch) {
+                       printk(KERN_WARNING "LTTng: event provider mismatch: "
+                               "The event name needs to start with provider "
+                               "name + _ + one or more letter, "
+                               "provider: %s, event name: %s\n",
+                               desc->provider_name, desc->event_desc[i]->event_name);
+                       return 0;
+               }
        }
        return 1;
 }