[PATCH v3] dl-load: add memory barrier before updating the next

[Torvald Riegel]

On Mon, 2017-04-03 at 16:58 +0530, Maninder Singh wrote:
> [BZ #21349]: race condition between dl_open and rtld lazy symbol resolve.
> 
> This patch adds C11 memory barrier before updating the liblist next.
> 
> Issue Fix: race condition between add_name_to_object  & _dl_name_match_p.
> One threads calling dlopen which further calls add_name_to_object &
> other thread trying to resolve RTLD_LAZY symbols through
> _dl_runtime_resolve which further calls.
> 
> _dl_name_match_p checks if libname->next is valid, then it assumes
> libname->next->name to be valid. Also add_name_to_object initialized
> name first and then sets valid next pointer.
> 
> This patch avoids any reorder of instruction when next is set before
> name to avoid any race.
> 
> Signed-off-by: Vaneet Narang <v.narang@samsung.com>
> Signed-off-by: Maninder Singh <maninder1.s@samsung.com>

Please address my comments on v2 of your patch too.