perf tools: Free 'printk' string in parse_ftrace_printk()

[ Upstream commit 9c8a182e5a73e01afd11742a2ab887bf338fdafd ]

parse_ftrace_printk() tokenizes and parses a line, calling strdup() each
iteration.  Add code to free this temporary format string duplicate.

Fixes the following coverity complaints:

  Error: RESOURCE_LEAK (CWE-772):
  tools/perf/util/trace-event-parse.c:158: overwrite_var: Overwriting
  "printk" in "printk = strdup(fmt + 1)" leaks the storage that "printk"
  points to.

  tools/perf/util/trace-event-parse.c:162: leaked_storage: Variable
  "printk" going out of scope leaks the storage it points to.
Signed-off-by: NSanskriti Sharma <sansharm@redhat.com>
Reviewed-by: NJiri Olsa <jolsa@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Link: http://lkml.kernel.org/r/1538490554-8161-4-git-send-email-sansharm@redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/perf/util/trace-event-parse.c

@@ -158,6 +158,7 @@ void parse_ftrace_printk(struct tep_handle *pevent,
 		printk = strdup(fmt+1);
 		line = strtok_r(NULL, "\n", &next);
 		tep_register_print_string(pevent, printk, addr);
+		free(printk);
 	}
 }