Commit 3dd1f7f2 authored May 07, 2019 by Masami Hiramatsu Committed by Steven Rostedt (VMware) May 08, 2019

tracing: probeevent: Fix to make the type of $comm string

Fix to make the type of $comm "string".  If we set the other type to $comm
argument, it shows meaningless value or wrong data. Currently probe events
allow us to set string array type (e.g. ":string[2]"), or other digit types
like x8 on $comm. But since clearly $comm is just a string data, it should
not be fetched by other types including array.

Link: http://lkml.kernel.org/r/155723736241.9149.14582064184468574539.stgit@devnote2



Cc: Andreas Ziegler <andreas.ziegler@fau.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 53305928 ("tracing: probeevent: Introduce new argument fetching code")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent 489fe009

kernel/trace/trace_probe.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -533,13 +533,14 @@ static int traceprobe_parse_probe_arg_body(char arg, ssize_t size,
		}
		}
		}
		/*
		* The default type of $comm should be "string", and it can't be
		* dereferenced.
		*/
		if (!t && strcmp(arg, "$comm") == 0)

		/* Since $comm can not be dereferred, we can find $comm by strcmp */
		if (strcmp(arg, "$comm") == 0) {
		/* The type of $comm must be "string", and not an array. */
		if (parg->count \|\| (t && strcmp(t, "string")))
		return -EINVAL;
		parg->type = find_fetch_type("string");
		else
		} else
		parg->type = find_fetch_type(t);
		if (!parg->type) {
		trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);

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