[PATCH v3 3/6] Initialize l_mach field from rtld link_map

Sandra Loosemore sloosemore@baylibre.com
Thu Sep 18 04:22:45 GMT 2025


On 9/17/25 15:08, Adhemerval Zanella Netto wrote:
> 
> 
> On 03/09/25 10:53, Jovan Dmitrovic wrote:
>> From: Aleksandar Rakic <aleksandar.rakic@htecgroup.com>
>>
>> Based on patch submitted by Sandra Loosemore:
>> https://sourceware.org/ml/libc-alpha/2015-03/msg00704.html
>>
>> For MIPS builds, l_mach field contains fpabi value.
>> If l_mach isn't zero-initialized, we may get dynamic linking
>> failures due to incompatible FP ABIs. Similar issue may arise
>> or is already present on other platforms.
>>
>> Reported-by: Sandra Loosemore <sandra@codesourcery.com>
>> ---
>>   elf/rtld.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/elf/rtld.c b/elf/rtld.c
>> index 753ce6690b..10bf816e7f 100644
>> --- a/elf/rtld.c
>> +++ b/elf/rtld.c
>> @@ -532,6 +532,7 @@ _dl_start (void *arg)
>>        do not have to use the temporary bootstrap_map.  Global variables
>>        are initialized to zero by default.  */
>>   #ifndef DONT_USE_BOOTSTRAP_MAP
>> +  bootstrap_map.l_mach = (struct link_map_machine) {};
>>   # ifdef HAVE_BUILTIN_MEMSET
>>     __builtin_memset (bootstrap_map.l_info, '\0', sizeof (bootstrap_map.l_info));
>>   # else
> 
> Even if compiler inlines the zero clearing, I think it would be better to
> follow the same strategy done for l_info and either user __builtin_memset
> or a open-coded memset.

That's what my original version of the patch did....  :-)

-Sandra


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