Re: [PATCH 1/5] selftests: Fix selftests build to just build, not run tests

[Shuah Khan <shuahkh@osg.samsung.com>]

Hi Michael and Bamovar,

On 03/01/2017 11:43 PM, Michael Ellerman wrote:
> Shuah Khan <shuahkh@osg.samsung.com> writes:
>> Hi Bamovar,
>>
>> Your original series badly broke the selftest build. I can no longer
>> build individual tests. For example:
>>
>> cd breakpoints/
>> shuah@shuah-XPS-13-9350:/lkml/linux_4.11/tools/testing/selftests/breakpoints$ make
>> gcc     breakpoint_test.c  -o /breakpoint_test
>> /usr/bin/ld: cannot open output file /breakpoint_test: Permission denied
>> collect2: error: ld returned 1 exit status
>> ../lib.mk:54: recipe for target '/breakpoint_test' failed
>> make: *** [/breakpoint_test] Error 1
> 
> I also got a report of that just yesterday.
> 
> You can do:
> 
> $ cd tools/testing/selftests ; make TARGETS=breakpoints
> 
> But it's not ideal.
> 
>> commit a8ba798bc8ec663cf02e80b0dd770324de9bafd9
>> Author: bamvor.zhangjian@huawei.com <bamvor.zhangjian@huawei.com>
>> Date:   Tue Nov 29 19:55:52 2016 +0800
>>
>>     selftests: enable O and KBUILD_OUTPUT
>>
>> I believe the above patch is one of the suspects. Michael fixed
>> some of the problems in this patch and others he sent.
> 
> It is that patch which caused it yes.
> 
>> At the moment individual tests will not build.
>> tools/testing/selftests/x86$ make
>> Makefile:44: warning: overriding recipe for target 'clean'
>> ../lib.mk:51: warning: ignoring old recipe for target 'clean'
>> gcc -m64 -o /single_step_syscall_64 -O2 -g -std=gnu99 -pthread -Wall  single_step_syscall.c -lrt -ldl
>> /usr/bin/ld: cannot open output file /single_step_syscall_64: Permission denied
>> collect2: error: ld returned 1 exit status
>> Makefile:50: recipe for target '/single_step_syscall_64' failed
>> make: *** [/single_step_syscall_64] Error 1
>>
>>
>> My guess is OUTPUT doesn't resolve in individual builds from the test directory.
>> We have to get this fixed for 4.11-rc1
> 
> Yeah, OUTPUT is passed down from the top-level Makefile.
> 
>> Simply Reverting a8ba798bc8ec663cf02e80b0dd770324de9bafd9 doesn't work.
>> Michael's patches depend on this. So anyway, please let me know if you
>> can fix this quickly. I am going to be trying a few things today as well.
> 
> This seems to work, but needs some testing with and without OUTPUT set.
> 
> Basically if OUTPUT is not set, assume the current directory. It should
> only take effect when someone builds from an individual directory,
> because if you build from the top level OUTPUT is already set.
> 
> 
> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
> index ce96d80ad64f..9087fa949e82 100644
> --- a/tools/testing/selftests/lib.mk
> +++ b/tools/testing/selftests/lib.mk
> @@ -2,6 +2,8 @@
>  # Makefile can operate with or without the kbuild infrastructure.
>  CC := $(CROSS_COMPILE)gcc
>  
> +OUTPUT ?= $(PWD)
> +
>  TEST_GEN_PROGS := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS))
>  TEST_GEN_FILES := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_FILES))
>  
> 
> 
> cheers
> 

I sent a fix to lib.mk to set the OUTPUT. Please review. I can request
Linus to merge it in before 4.11-rc1 comes out.

thanks,
-- Shuah