On 9 February 2016 at 11:31, David Gwynne <da...@gwynne.id.au> wrote: > On Mon, Feb 08, 2016 at 11:02:06PM +1000, David Gwynne wrote: >> On Sat, Feb 06, 2016 at 04:43:28PM -0500, Anthony Eden wrote: >> > >Synopsis: <alignment fault on armv7 (omap) using carp(4)> >> > >> > To me that behavior might suggest the problem is deeper than a >> > bookkeeping mistake of aligning memory in mbuf. >> >> nope, you were right, it's a screwup with alignment. >> >> the problem is multicast packets that arent to a carp interfaces >> mac address have to be duplicated and sent to all carp interfaces >> on a parent. the duplication is done with m_copym2, which doesn't >> respect the alignment requirements of the ip header inside the 14 >> byte ethernet header. >> >> the following dups the packet inside carp, and makes sure the >> ethernet payload is aligned properly. >> >> i was able to reproduce this on sparc64, and i believe this fixes >> it. could you test it and see if it helps? > > mpi@ pointed out that bridge@ has a special function to do a deep > copy of mbufs that get the ip payload alignment right, and that we > should share. > > this moves the functionality in with the rest of the mbuf functions. > > could a bridge user test this to see if it still works? carp seems > fine with this on sparc64 stil. > > ok? >
m_adj can be done as part of the m_copym2 as well. In the long run I don't think that introducing a new function makes sense, not sure about 5.9 and right now, though.
