tracing/probe: Have traceprobe_parse_probe_arg() take a const arg

The two places that call traceprobe_parse_probe_arg() allocate a temporary
buffer to copy the argv[i] into, because argv[i] is constant and the
traceprobe_parse_probe_arg() will modify it to do the parsing. These two
places allocate this buffer and then free it right after calling this
function, leaving the onus of this allocation to the caller.

As there's about to be a third user of this function that will have to do
the same thing, instead of having the caller allocate the temporary
buffer, simply move that allocation into the traceprobe_parse_probe_arg()
itself, which will simplify the code of the callers.

Link: https://lkml.kernel.org/r/20210817035027.385422828@goodmis.org

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 1 insertions, 8 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 82c3b86013b2..ed1e3c2087ab 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -873,15 +873,8 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 
 	/* parse arguments */
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
-		tmp = kstrdup(argv[i], GFP_KERNEL);
-		if (!tmp) {
-			ret = -ENOMEM;
-			goto error;
-		}
-
 		trace_probe_log_set_index(i + 2);
-		ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
-		kfree(tmp);
+		ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], flags);
 		if (ret)
 			goto error;	/* This can be -ENOMEM */
 	}