[RFC 4/5] elf: Enable RTLD_NODELETE on __libc_unwind_link_get

[Adhemerval Zanella Netto]

On 12/06/24 06:54, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> The libgcc_s.so can also be sealed.  The library is loaded once
>> and not unloaded during process execution (only for memory debug
>> with __libc_unwind_link_freeres).
> 
> The unwind-link change to use RTLD_NODELETE could go in separately.

Ok, I will send a separate patch.

> 
>> diff --git a/misc/unwind-link.c b/misc/unwind-link.c
>> index 213a0162a4..7267ecbec3 100644
>> --- a/misc/unwind-link.c
>> +++ b/misc/unwind-link.c
> 
>> @@ -100,7 +100,8 @@ __libc_unwind_link_get (void)
>>  
>>    __libc_lock_lock (lock);
>>    if (atomic_load_relaxed (&global_libgcc_handle) != NULL)
>> -    /* This thread lost the race.  Clean up.  */
>> +    /* This thread lost the race.  Drop the l_direct_opencount and issue
>> +       the debug log.  */
>>      __libc_dlclose (local_libgcc_handle);
>>    else
>>      {
> 
> I don't understand what “debug log” means in this context.

Sorry, I meant the __libc_unwind_link_freeres usually triggered by
memory profilers.  With sealing the dlclose won't unmap the memory.