Re: [PATCH] elf: Remove dead l_need_tls_init static-TLS init path

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 10/06/26 04:33, Florian Weimer wrote:
> * Adhemerval Zanella Netto:
> 
>> On 09/06/26 11:13, Florian Weimer wrote:
>>> * Adhemerval Zanella:
>>>
>>>> @@ -671,16 +641,18 @@ dl_open_worker_begin (void *a)
>>>>    if (mode & RTLD_GLOBAL)
>>>>      add_to_global_resize (new);
>>>>  
>>>> -  /* Install the new modules in the DTV slotinfo and initialise their
>>>> -     static TLS *before* relocation, so an IFUNC resolver firing during
>>>> -     the relocation loop below can reach its DSO's __thread storage via
>>>> -     __tls_get_addr / TLSDESC.  Without this, the resolver's TLS access
>>>> -     for a just-loaded module would index into an unallocated DTV slot
>>>> -     and crash.  If relocation later fails, the subsequent _dl_close_worker
>>>> -     cleans up these slotinfo entries via remove_slotinfo.  */
>>>> +  /* Register the new modules in the DTV slotinfo and bump the TLS
>>>> +     generation counter *before* relocation, so an IFUNC resolver firing
>>>> +     during the relocation loop below can reach its DSO's __thread storage
>>>> +     via __tls_get_addr / TLSDESC.  Without this, the new module is not yet
>>>> +     in GL(dl_tls_dtv_slotinfo_list), so the resolver's dynamic-TLS lookup
>>>> +     fails to find it and faults.  The static-TLS image itself is copied
>>>> +     lazily on first access; for the initial-exec model the static-TLS
>>>> +     offset is reserved inline during relocation (see
>>>> +     _dl_try_allocate_static_tls), not here.  If relocation later fails,
>>>> +     the subsequent _dl_close_worker cleans up these slotinfo entries via
>>>> +     remove_slotinfo.  */
>>>>    if (any_tls)
>>>> -    /* FIXME: This calls _dl_update_slotinfo, which aborts the process
>>>> -       on memory allocation failure.  See bug 16134.  */
>>>>      update_tls_slotinfo (new);
>>>
>>> Is the FIXME truly gone?
>> No, BZ 16134 is not fixed, only relocated. That lazy path still aborts:
>>   
>>   __tls_get_addr -> _dl_update_slotinfo -> _dl_resize_dtv -> oom
>>
>> Per:
>>
>> elf/dt-tls.c
>>
>>  921                   /* Resizing the dtv aborts on failure: bug 16134.  */
>>  922                   dtv = _dl_resize_dtv (dtv, max_modid, THREAD_SELF);
> 
> Sorry, then why remove the comment?
> 
> Thanks,
> Florian
>

Because with this cleanup update_tls_slotinfo does not call _dl_update_slotinfo,
so the bug does happen at this call anymore.