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-rw-r--r--kernel/tracepoint.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 0d4ef26..0058f33 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -62,6 +62,7 @@ struct tracepoint_entry {
struct hlist_node hlist;
struct tracepoint_func *funcs;
int refcount; /* Number of times armed. 0 if disarmed. */
+ int enabled; /* Tracepoint enabled */
char name[0];
};
@@ -237,6 +238,7 @@ static struct tracepoint_entry *add_tracepoint(const char *name)
memcpy(&e->name[0], name, name_len);
e->funcs = NULL;
e->refcount = 0;
+ e->enabled = 0;
hlist_add_head(&e->hlist, head);
return e;
}
@@ -316,6 +318,7 @@ static void tracepoint_update_probe_range(struct tracepoint * const *begin,
if (mark_entry) {
set_tracepoint(&mark_entry, *iter,
!!mark_entry->refcount);
+ mark_entry->enabled = !!mark_entry->refcount;
} else {
disable_tracepoint(*iter);
}
@@ -380,6 +383,8 @@ tracepoint_add_probe(const char *name, void *probe, void *data)
int tracepoint_probe_register(const char *name, void *probe, void *data)
{
struct tracepoint_func *old;
+ struct tracepoint_entry *entry;
+ int ret = 0;
mutex_lock(&tracepoints_mutex);
old = tracepoint_add_probe(name, probe, data);
@@ -388,9 +393,13 @@ int tracepoint_probe_register(const char *name, void *probe, void *data)
return PTR_ERR(old);
}
tracepoint_update_probes(); /* may update entry */
+ entry = get_tracepoint(name);
+ /* Make sure the entry was enabled */
+ if (!entry || !entry->enabled)
+ ret = -ENODEV;
mutex_unlock(&tracepoints_mutex);
release_probes(old);
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
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