[for-linus][PATCH 5/5] tracing: Create output file from cmd_check_undefined

[Steven Rostedt <rostedt@kernel.org>]

From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= <linux@weissschuh.net>

As the output file is currently never created, the check will run every
time, even if the inputs have not changed.

Create an empty output file which allows make to skip the execution when
it is not necessary.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20260520-tracing-ringbuffer-check-v1-1-d979cfab1338@weissschuh.net
Fixes: 1211907ac0b5 ("tracing: Generate undef symbols allowlist for simple_ring_buffer")
Fixes: 58b4bd18390e ("tracing: Adjust cmd_check_undefined to show unexpected undefined symbols")
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 9b0834134cae..8d3d96e847d8 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -154,7 +154,8 @@ quiet_cmd_check_undefined = NM      $<
               echo "Unexpected symbols in $<:" >&2; \
               echo "$$undefsyms" >&2; \
               false; \
-          fi
+          fi; \
+          touch $@
 
 $(obj)/%.o.checked: $(obj)/%.o $(obj)/undefsyms_base.o FORCE
 	$(call if_changed,check_undefined)
-- 
2.53.0