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

[Carlos O'Donell]

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.

-- 
Cheers,
Carlos.