[dpdk-dev] [PATCH] librte_eal: fix mcslock hang on weak memory

[Thomas Monjalon]

> >     The initialization me->locked=1 in lock() must happen before
> >     next->locked=0 in unlock(), otherwise a thread may hang forever,
> >     waiting me->locked become 0. On weak memory systems (such as ARMv8),
> >     the current implementation allows me->locked=1 to be reordered with
> >     announcing the node (pred->next=me) and, consequently, to be
> >     reordered with next->locked=0 in unlock().
> > 
> >     This fix adds a release barrier to pred->next=me, forcing
> >     me->locked=1 to happen before this operation.
> > 
> > Signed-off-by: Diogo Behrens <diogo.behrens at huawei.com>
> The change looks fine to me.  I have tested this on few x86 and Arm machines.
> Acked-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>

Applied, thanks