[PATCH 6.1 240/609] tracing/eprobe: Fix exact system name matching in eprobe_dyn_event_match()

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Masami Hiramatsu (Google) <[email protected]>

commit f418d68d71fd4a0a9cef92377bc8c4c3334b5b53 upstream.

eprobe_dyn_event_match() checks if the target event system in argv[0]
matches ep->event_system using strncmp(ep->event_system, argv[0], len).
However, if ep->event_system is longer than len (e.g. "eprobes" vs
"ep/event"), strncmp() still returns 0 because the first len characters
match.

Check that ep->event_system[len] is '\0' to ensure exact system name
matching.

Link: https://lore.kernel.org/all/178454235856.290363.14872590900774231133.stgit@devnote2/

Fixes: 7d5fda1c841f ("tracing: Fix event probe removal from dynamic events")
Cc: [email protected]
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 kernel/trace/trace_eprobe.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -164,7 +164,8 @@ static bool eprobe_dyn_event_match(const
 	if (!slash)
 		return false;
 
-	if (strncmp(ep->event_system, argv[0], slash - argv[0]))
+	if (strncmp(ep->event_system, argv[0], slash - argv[0]) ||
+	    ep->event_system[slash - argv[0]] != '\0')
 		return false;
 	if (strcmp(ep->event_name, slash + 1))
 		return false;