On Fri, 2020-03-27 at 09:53:19 UTC, Michael Ellerman wrote: > 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: sta...@vger.kernel.org # v5.5+ > Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Applied to powerpc next. https://git.kernel.org/powerpc/c/9686813f6e9d5568bc045de0be853411e44958c8 cheers