From 625b4439bebdfb122eabf2100c3c7c5f549a514e Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 27 Mar 2020 20:53:19 +1100 Subject: selftests/powerpc: Fix try-run when source tree is not writable commit 9686813f6e9d5568bc045de0be853411e44958c8 upstream. We added a usage of try-run to pmu/ebb/Makefile to detect if the toolchain supported the -no-pie option. This fails if we build out-of-tree and the source tree is not writable, as try-run tries to write its temporary files to the current directory. That leads to the -no-pie option being silently dropped, which leads to broken executables with some toolchains. If we remove the redirect to /dev/null in try-run, we see the error: make[3]: Entering directory '/linux/tools/testing/selftests/powerpc/pmu/ebb' /usr/bin/ld: cannot open output file .54.tmp: Read-only file system collect2: error: ld returned 1 exit status make[3]: Nothing to be done for 'all'. And looking with strace we see it's trying to use a file that's in the source tree: lstat("/linux/tools/testing/selftests/powerpc/pmu/ebb/.54.tmp", 0x7ffffc0f83c8) We can fix it by setting TMPOUT to point to the $(OUTPUT) directory, and we can verify with strace it's now trying to write to the output directory: lstat("/output/kselftest/powerpc/pmu/ebb/.54.tmp", 0x7fffd1bf6bf8) And also see that the -no-pie option is now correctly detected. Fixes: 0695f8bca93e ("selftests/powerpc: Handle Makefile for unrecognized option") Cc: stable@vger.kernel.org # v5.5+ Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200327095319.2347641-1-mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/powerpc/pmu/ebb/Makefile | 1 + 1 file changed, 1 insertion(+) (limited to 'tools') diff --git a/tools/testing/selftests/powerpc/pmu/ebb/Makefile b/tools/testing/selftests/powerpc/pmu/ebb/Makefile index 417306353e07..ca35dd8848b0 100644 --- a/tools/testing/selftests/powerpc/pmu/ebb/Makefile +++ b/tools/testing/selftests/powerpc/pmu/ebb/Makefile @@ -7,6 +7,7 @@ noarg: # The EBB handler is 64-bit code and everything links against it CFLAGS += -m64 +TMPOUT = $(OUTPUT)/ # Toolchains may build PIE by default which breaks the assembly no-pie-option := $(call try-run, echo 'int main() { return 0; }' | \ $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -no-pie -x c - -o "$$TMP", -no-pie) -- cgit v1.2.3