On Wed, 5 Jun 2024 at 01:03, Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx> wrote: > > Magnus Karlsson wrote: > > Revert "xsk: support redirect to any socket bound to the same umem" > > > > This patch introduced a potential kernel crash when multiple napi > > instances redirect to the same AF_XDP socket. By removing the > > queue_index check, it is possible for multiple napi instances to > > access the Rx ring at the same time, which will result in a corrupted > > ring state which can lead to a crash when flushing the rings in > > __xsk_flush(). This can happen when the linked list of sockets to > > flush gets corrupted by concurrent accesses. A quick and small fix is > > unfortunately not possible, so let us revert this for now. > > This is a very useful feature, to be able to use AF_XDP sockets with > a standard RSS nic configuration. I completely agree. > Not all AF_XDP use cases require the absolute highest packet rate. > > Can this be addressed with an optional spinlock on the RxQ, only for > this case? Yes, or with a MPSC ring implementation. > If there is no simple enough fix in the short term, do you plan to > reintroduce this in another form later? Yuval and I are looking into a solution based around an optional spinlock since it is easier to pull off than an MPSC ring. The discussion is on-going on the xdp-newbies list [0], but as soon as we have a first patch, we will post it here for review and debate. [0] https://lore.kernel.org/xdp-newbies/8100DBDC-0B7C-49DB-9995-6027F6E63147@xxxxxxxxxxx/
