Commit 30460c21 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google)
Browse files

tracing/probes: Avoid setting TPARG_FL_FENTRY and TPARG_FL_RETURN 

When parsing a kprobe event, the return probe always sets both
TPARG_FL_RETURN and TPARG_FL_FENTRY, but this is not useful because
some fetchargs are only for return probe and some others only for
function entry. Make it obviously mutual exclusive.

Link: https://lore.kernel.org/all/168507468731.913472.11354553441385410734.stgit@mhiramat.roam.corp.google.com/



Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
parent cb16330d

kernel/trace/trace_kprobe.c

+1 −1
Original line number Diff line number Diff line
@@ -825,7 +825,7 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
		if (is_return)

			flags |= TPARG_FL_RETURN;

		ret = kprobe_on_func_entry(NULL, symbol, offset);

		if (ret == 0)

		if (ret == 0 && !is_return)

			flags |= TPARG_FL_FENTRY;

		/* Defer the ENOENT case until register kprobe */

		if (ret == -EINVAL && is_return) {

kernel/trace/trace_probe.h

+5 −0
Original line number Diff line number Diff line
@@ -357,6 +357,11 @@ int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_a 
#define trace_probe_for_each_link_rcu(pos, tp)	\

	list_for_each_entry_rcu(pos, &(tp)->event->files, list)



/*

 * The flags used for parsing trace_probe arguments.

 * TPARG_FL_RETURN, TPARG_FL_FENTRY and TPARG_FL_TPOINT are mutually exclusive.

 * TPARG_FL_KERNEL and TPARG_FL_USER are also mutually exclusive.

 */

#define TPARG_FL_RETURN BIT(0)

#define TPARG_FL_KERNEL BIT(1)

#define TPARG_FL_FENTRY BIT(2)