Re: [PATCH] ld: Require GCC 8.0 for p_align-1.c tests

[Jan Beulich <jbeulich@suse.com>]

On 17.01.2022 14:44, H.J. Lu wrote:
> On Mon, Jan 17, 2022 at 2:38 AM Jan Beulich <jbeulich@suse.com> wrote:
>>
>> On 14.01.2022 15:14, H.J. Lu wrote:
>>> On Fri, Jan 14, 2022 at 6:08 AM Jan Beulich <jbeulich@suse.com> wrote:
>>>>
>>>> On 14.01.2022 15:02, H.J. Lu wrote:
>>>>> On Fri, Jan 14, 2022 at 5:40 AM Jan Beulich <jbeulich@suse.com> wrote:
>>>>>>
>>>>>> On 14.01.2022 14:03, H.J. Lu wrote:
>>>>>>> On Fri, Jan 14, 2022 at 12:27 AM Jan Beulich <jbeulich@suse.com> wrote:
>>>>>>>>
>>>>>>>> On 29.12.2021 20:39, H.J. Lu via Binutils wrote:
>>>>>>>>> --- a/ld/testsuite/ld-elf/linux-x86.exp
>>>>>>>>> +++ b/ld/testsuite/ld-elf/linux-x86.exp
>>>>>>>>> @@ -185,6 +185,42 @@ run_ld_link_exec_tests [list \
>>>>>>>>>       "" \
>>>>>>>>>       "tmpdir/indirect-extern-access-2.so" \
>>>>>>>>>      ] \
>>>>>>>>> +    [list \
>>>>>>>>> +     "Run p_align-1a without PIE" \
>>>>>>>>> +     "$NOPIE_LDFLAGS" \
>>>>>>>>> +     "" \
>>>>>>>>> +     { p_align-1.c } \
>>>>>>>>> +     "p_align-1a" \
>>>>>>>>> +     "pass.out" \
>>>>>>>>> +     "$NOPIE_CFLAGS" \
>>>>>>>>> +    ] \
>>>>>>>>> +    [list \
>>>>>>>>> +     "Run p_align-1b with PIE" \
>>>>>>>>> +     "-pie" \
>>>>>>>>> +     "" \
>>>>>>>>> +     { p_align-1.c } \
>>>>>>>>> +     "p_align-1b" \
>>>>>>>>> +     "pass.out" \
>>>>>>>>> +     "-fpie" \
>>>>>>>>> +    ] \
>>>>>>>>> +    [list \
>>>>>>>>> +     "Run p_align-1c with -Wl,-z,max-page-size=0x1000 without PIE" \
>>>>>>>>> +     "$NOPIE_LDFLAGS -Wl,-z,max-page-size=0x1000" \
>>>>>>>>> +     "" \
>>>>>>>>> +     { p_align-1.c } \
>>>>>>>>> +     "p_align-1c" \
>>>>>>>>> +     "pass.out" \
>>>>>>>>> +     "$NOPIE_CFLAGS" \
>>>>>>>>> +    ] \
>>>>>>>>> +    [list \
>>>>>>>>> +     "Run p_align-1d with -Wl,-z,max-page-size=0x1000 with PIE" \
>>>>>>>>> +     "-pie -Wl,-z,max-page-size=0x1000" \
>>>>>>>>> +     "" \
>>>>>>>>> +     { p_align-1.c } \
>>>>>>>>> +     "p_align-1d" \
>>>>>>>>> +     "pass.out" \
>>>>>>>>> +     "-fpie" \
>>>>>>>>> +    ] \
>>>>>>>>>  ]
>>>>>>>>
>>>>>>>> The two PIE variants of this also fail for me on glibc 2.26. Looks
>>>>>>>> like LOAD segments' alignment isn't being honored there, at least
>>>>>>>> not if it's as big as it is here.
>>>>>>>>
>>>>>>>
>>>>>>> The PIE alignment needs the kernel fix:
>>>>>>>
>>>>>>> commit ce81bb256a224259ab686742a6284930cbe4f1fa
>>>>>>> Author: Chris Kennelly <ckennelly@google.com>
>>>>>>> Date:   Thu Oct 15 20:12:32 2020 -0700
>>>>>>>
>>>>>>>     fs/binfmt_elf: use PT_LOAD p_align values for suitable start address
>>>>>>
>>>>>> Well, then the test needs to be skipped if that fix is not in place.
>>>>>> After all you're testing binutils behavior here, not kernel or libc one.
>>>>>> I'm running a variety of (largely up-to-date) kernels on all of my
>>>>>> systems. But it looks like our kernel folks decided against backporting
>>>>>> this particular change. And I don't think you expect people to remember
>>>>>> to run the testsuite only on top of "certain" kernels?
>>>>>
>>>>> Care to submit a patch?
>>>>
>>>> I have no idea what to check for. I would really expect you to fix such
>>>> an issue (or really two of them, considering the other problem) recently
>>>> introduced by you.
>>>
>>> What compiler are you using on the broken kernel?
>>
>> gcc 7.4.1
>>
>> No idea how that matters, though.
> 
> Try this.

I can see that this might help with the other problem I did report, but I
don't see how gcc version and kernel in use would correlate. I guess I
could build binutils on that box with gcc 11, and then the kernel still
wouldn't do what you expect it to do. Much like I could continue using
gcc 7 and use a newer kernel, and then the test would be skipped for no
reason.

What I don't understand is why this needs to be a "run" test in the first
place. You're only after checking that the produced binary is correct,
aren't you?

Jan