We do a light flush on CLIENT_REREG and SM_CHANGE events. This goes through and marks paths invalid. But we weren't always checking for this validity when we needed to, and so we could keep using a path marked invalid. What's more, once we establish a path with a valid ah, we put a pointer to the ah in the neigh struct directly, so even if we mark the path as invalid, as long as the neigh has a direct pointer to the ah, it keeps using the old, outdated ah. To fix this we do several things. 1) Put the valid flag in the ah instead of the path struct, so when we put the ah pointer directly in the neigh struct, we can easily check the validity of the ah on send events. 2) Check the neigh->ah and neigh->ah->valid elements in the needed places, and if we have an ah, but it's invalid, then invoke a refresh of the ah. 3) Fix the various places that check for path, but didn't check for path->valid (now path->ah && path->ah->valid). Reported-by: Evgenii Smirnov <evgenii.smirnov@profitbricks.com> Fixes: ee1e2c82c245 ("IPoIB: Refresh paths instead of flushing them on SM change events") Signed-off-by: Doug Ledford <dledford@redhat.com>