markers: fix unchecked format

when the second, third... probe is registered, its format is
not checked, this patch fixes it.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 9 insertions, 3 deletions

diff --git a/kernel/marker.c b/kernel/marker.c
index 05a25776f71f..3b75d0e8b5a4 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -653,11 +653,17 @@ int marker_probe_register(const char *name, const char *format,
         entry = get_marker(name);
         if (!entry) {
                 entry = add_marker(name, format);
-                if (IS_ERR(entry)) {
+                if (IS_ERR(entry))
                         ret = PTR_ERR(entry);
-                        goto end;
-                }
+        } else if (format) {
+                if (!entry->format)
+                        ret = marker_set_format(&entry, format);
+                else if (strcmp(entry->format, format))
+                        ret = -EPERM;
         }
+        if (ret)
+                goto end;
+
         /*
          * If we detect that a call_rcu is pending for this marker,
          * make sure it's executed now.