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Re: [PATCH 2/2] linux: Make profil_counter a compat_symbol (BZ#17726)
On 02/08/2019 08:09, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>> As indicated by Joseph's comment on BZ#17726, this symbol is most
>> likely a historical ABI accident. This patch make it on both arm
>> and sparc ABIs a compat_symbol.
>>
>> Checked with a build arm-linux-gnueabihf, sparcv9-linux-gnu, adn
>> sparc64-linux-gnu to see if the symbol is still present.
>>
>> * gmon/Versions (libc) [GLIBC_2.31]: New entry.
>> * sysdeps/unix/sysv/linux/arm/profil-counter.h (profil_counter):
>> Make a compat_symbol.
>> * sysdeps/unix/sysv/linux/sparc/profil-counter.h
>> (__profil_counter_global): Likewise.
>
> There is this bug:
>
> <https://sourceware.org/bugzilla/show_bug.cgi?id=14043>
>
> So it was already gone for over four years on arm until someone noticed.
> I wonder if something really needs it?
My take on this accidental ABI leakage is just to dropped it, it exposes
unnecessary implementation detail, add complexity on arch-specific code
base, it is dangerous because pollute application namespace with non
expected symbol, and I would consider a potential bug if application are
relying on this specific symbol semantic (and it is also non-portable).
So I would vote if we just remove it instead of make it a compat symbol.