[PATCH] kselftest/arm64: signal: copy each test binary only once

[PATCH] kselftest/arm64: signal: copy each test binary only once

[Sasha Levin]

The signal tests are built in testcases/ and then copied to the output
directory. The copy rule lists every generated program as a target and
copies all of them in each recipe:

  $(TEST_GEN_PROGS): $(PROGS)
          cp $(PROGS) $(OUTPUT)/

In a parallel build make runs that recipe once for each program, so
several cp processes write the same destination files at the same time.
cp then fails with "cannot create regular file ...: File exists", which
fails the arm64 build even though every test compiled. A cross build of
the arm64 signal tests at -j8 hit this in all of 8 runs.

Use a static pattern rule so that each output depends on, and copies,
only its own binary.

Fixes: f96bf4340316 ("kselftest: arm64: mangle_pstate_invalid_compat_toggle and common utils")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/arm64/signal/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/arm64/signal/Makefile b/tools/testing/selftests/arm64/signal/Makefile
index 1381039fb36f9..c4df4be41636c 100644
--- a/tools/testing/selftests/arm64/signal/Makefile
+++ b/tools/testing/selftests/arm64/signal/Makefile
@@ -17,8 +17,8 @@ TEST_GEN_PROGS := $(notdir $(PROGS))
 # the toplevel makefile
 include ../../lib.mk
 
-$(TEST_GEN_PROGS): $(PROGS)
-	cp $(PROGS) $(OUTPUT)/
+$(TEST_GEN_PROGS): $(OUTPUT)/%: testcases/%
+	cp $< $@
 
 # Common test-unit targets to build common-layout test-cases executables
 # Needs secondary expansion to properly include the testcase c-file in pre-reqs

base-commit: 4eb2586bd40db27d77cc5b724ca9386ed0c71d53
-- 
2.53.0