selftests/bpf: use canonical ftrace path

The canonical location for the tracefs filesystem is at
/sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

  Before 4.1, all ftrace tracing control files were within the debugfs
  file system, which is typically located at /sys/kernel/debug/tracing.
  For backward compatibility, when mounting the debugfs file system,
  the tracefs file system will be automatically mounted at:

  /sys/kernel/debug/tracing

Many tests in the bpf selftest code still refer to this older debugfs
path, so let's update them to avoid confusion.

Signed-off-by: Ross Zwisler <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Steven Rostedt (Google) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

1 files changed, 7 insertions, 2 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c b/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c
index 770fcc3bb1ba..655d69f0ff0b 100644
--- a/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c
+++ b/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c
@@ -16,8 +16,13 @@ void serial_test_tp_attach_query(void)
 	for (i = 0; i < num_progs; i++)
 		obj[i] = NULL;
 
-	snprintf(buf, sizeof(buf),
-		 "/sys/kernel/debug/tracing/events/sched/sched_switch/id");
+	if (access("/sys/kernel/tracing/trace", F_OK) == 0) {
+		snprintf(buf, sizeof(buf),
+			 "/sys/kernel/tracing/events/sched/sched_switch/id");
+	} else {
+		snprintf(buf, sizeof(buf),
+			 "/sys/kernel/debug/tracing/events/sched/sched_switch/id");
+	}
 	efd = open(buf, O_RDONLY, 0);
 	if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
 		return;