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Re: [glibc] nptl: Add missing placeholder abi symbol from nanosleep move
On 07/11/2019 14:21, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>> On 07/11/2019 13:54, Florian Weimer wrote:
>>> * Adhemerval Zanella:
>>>
>>>> https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4f4bb489e0ddd2f24b2a5d352bb39f8dcdb38050
>>>>
>>>> commit 4f4bb489e0ddd2f24b2a5d352bb39f8dcdb38050
>>>> Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>>>> Date: Thu Nov 7 15:10:35 2019 +0000
>>>>
>>>> nptl: Add missing placeholder abi symbol from nanosleep move
>>>>
>>>> Adds the __libpthread_version_placeholder symbol with the same version
>>>> of nanosleep/__nanosleep that was removed by 79a547b162657b3f and that
>>>> is not provided by other symbols.
>>>
>>>> +GLIBC_2.2 __libpthread_version_placeholder F
>>>
>>> Sorry, this fix does not look correct to me. Since GLIBC_2.2 has
>>> members (and we can easily detect that), it should not get an additional
>>> placeholder symbol.
>>>
>>> I think you need to add a symbol alias and another compat_symbol to
>>> nptl/libpthread-compat.c.
>>
>> It is not strictly incorrect, although superfluous. Ideally we would need
>> to add __libpthread_version_placeholder iff there is no other symbol with
>> same version already present, however I don't see straightforward to optimize
>> the symbol creation without adding some compat symbol hacking.
>
> This change does not look correct:
>
> -#if (SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_2))
> +#if (SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_2_6))
>
> You need
>
> #if (SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_2) \
> || SHLIB_COMPAT (libpthread, GLIBC_2_1_6, GLIBC_2_3))
Ack.
>
> and then do something like this:
>
> #if (SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_2))
> strong_alias (__libpthread_version_placeholder,
> __libpthread_version_placeholder_212)
> compat_symbol (libpthread, __libpthread_version_placeholder_212,
> __libpthread_version_placeholder, GLIBC_2_1_2);
> #endif
> #if (SHLIB_COMPAT (libpthread, GLIBC_2_1_6, GLIBC_2_3))
> strong_alias (__libpthread_version_placeholder,
> __libpthread_version_placeholder_226)
> compat_symbol (libpthread, __libpthread_version_placeholder_226,
> __libpthread_version_placeholder, GLIBC_2_2_6);
> #endif
>
> The strong_alias is needed because some binutils version/target
> combinations do not support multiple versions for one symbol.
>
Yeah, I indeed noted this binutils behaviour. Alright, sorry for the
trouble, I will send an updated version.