Re: [PATCH v3] elf: Fix DTV gap reuse logic (BZ #27135)

[Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>]

On 14/07/2021 13:57, Carlos O'Donell wrote:
> On 7/14/21 9:52 AM, Adhemerval Zanella wrote:
>>
>>
>> On 09/07/2021 12:05, Szabolcs Nagy wrote:
>>> The 07/09/2021 10:50, Adhemerval Zanella wrote:
>>>> Changes from previous version:
>>>>
>>>>   - Fix commit message and add a line about the bug fixes.
>>>>   - Use atomic operation while setting the slotinfo.
>>>>   - Use test_verbose on tst-tls20.c.
>>>>
>>>> ---
>>>>
>>>> This is updated version of the 572bd547d57a (reverted by 40ebfd016ad2)
>>>> that fixes the _dl_next_tls_modid issues.
>>>>
>>>> This issue with 572bd547d57a patch is the DTV entry will be only
>>>> update on dl_open_worker() with the update_tls_slotinfo() call after
>>>> all dependencies are being processed by _dl_map_object_deps().  However
>>>> _dl_map_object_deps() itself might call _dl_next_tls_modid(), and since
>>>> the _dl_tls_dtv_slotinfo_list::map is not yet set the entry will be
>>>> wrongly reused.
>>>>
>>>> This patch fixes by renaming the _dl_next_tls_modid() function to
>>>> _dl_assign_tls_modid() and by passing the link_map so it can set
>>>> the slotinfo value so a so subsequente _dl_next_tls_modid() call will
>>>> see the entry as allocated.
>>>
>>> this paragraph still has 'so a so subsequente'
>>> and i would add the bug number into the first sentence.
>>
>> Fixed.
>>
>>>
>>>>
>>>> The intermediary value is cleared up on remove_slotinfo() for the case
>>>> a library fails to load with RTLD_NOW.
>>>>
>>>> This patch fixes BZ #27135.
>>>>
>>>> Checked on x86_64-linux-gnu.
>>>
>>> the patch looks ok to me, with the commit message
>>> and the comment issue below fixed.
>>>
>>> Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
>>
>> Carlos, is it for push?
> 
> It's a non-ABI bug fix, so we can push it. Thanks for asking.
> 

And it is in, let's hope it does not brake anything again ;)