Commit 56e6a349 authored Jan 01, 2025 by Linus Torvalds

linux-trace

Pull tracing fix from Steven Rostedt:
 "Fix trace event string check when dealing with array of strings

  The xe_bo_move event has a field that indexes into an array of
  strings. The TP_fast_assign() added the index into the ring buffer and
  the TP_printk() had a "%s" that referenced the array using the index
  in the ring buffer. This is a legitimate use of "%s" in trace events.
  But this triggered a false positive in the test_event_printk() at boot
  saying that the string was dangerous.

  Change the check to allow arrays using fields in the ring buffer as an
  index to be considered a safe string"

* tag 'trace-v6.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Have process_string() also allow arrays

parents ccb98cce afc67176

kernel/trace/trace_events.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -364,6 +364,18 @@ static bool process_string(const char fmt, int len, struct trace_event_call ca
		s = r + 1;
		} while (s < e);

		/*
		* Check for arrays. If the argument has: foo[REC->val]
		* then it is very likely that foo is an array of strings
		* that are safe to use.
		*/
		r = strstr(s, "[");
		if (r && r < e) {
		r = strstr(r, "REC->");
		if (r && r < e)
		return true;
		}

		/*
		* If there's any strings in the argument consider this arg OK as it
		* could be: REC->field ? "foo" : "bar" and we don't want to get into