Commit f0228146 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-v5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull trace event string verifier fix from Steven Rostedt:
 "The run-time string verifier checks all trace event formats as
  they are read from the tracing file to make sure that the %s pointers
  are not reading something that no longer exists.

  However, it failed to account for the valid case of '%*.s' where the
  length given is zero, and the string is NULL. It incorrectly flagged
  it as a null pointer dereference and gave a WARN_ON()"

* tag 'trace-v5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Have trace event string test handle zero length strings
parents 710f5d62 eca344a7

kernel/trace/trace.c

+7 −2
Original line number Diff line number Diff line
@@ -3673,12 +3673,17 @@ static char *trace_iter_expand_format(struct trace_iterator *iter) 
}



/* Returns true if the string is safe to dereference from an event */

static bool trace_safe_str(struct trace_iterator *iter, const char *str)

static bool trace_safe_str(struct trace_iterator *iter, const char *str,

			   bool star, int len)

{

	unsigned long addr = (unsigned long)str;

	struct trace_event *trace_event;

	struct trace_event_call *event;



	/* Ignore strings with no length */

	if (star && !len)

		return true;



	/* OK if part of the event data */

	if ((addr >= (unsigned long)iter->ent) &&

	    (addr < (unsigned long)iter->ent + iter->ent_size))
@@ -3864,7 +3869,7 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, 
		 * instead. See samples/trace_events/trace-events-sample.h

		 * for reference.

		 */

		if (WARN_ONCE(!trace_safe_str(iter, str),

		if (WARN_ONCE(!trace_safe_str(iter, str, star, len),

			      "fmt: '%s' current_buffer: '%s'",

			      fmt, show_buffer(&iter->seq))) {

			int ret;