From: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> Date: Mon, 10 Dec 2012 19:45:52 +0100 > On Mon, 2012-12-10 at 13:41 -0500, David Miller wrote: >> So the bug is that ip_check_defrag() has a precondition which is met >> properly by all callers except AF_PACKET. >> >> If this is the case, remind me why are we changing ip_check_defrag() >> rather than the violator of the precondition? > > I don't think this is the case. > > If you're referring to my note about af_packet: the kernels where this > goes into af_packet.c are the kernels that don't even have > ip_check_defrag() because macvlan didn't exist/didn't have ip defrag > support and af_packet had this code there -- see commit bc416d9768a. > > If you're not referring to my note about af_packet: both callers (there > are only two) of ip_check_defrag() have this bug as far as I can tell > because they're both in the part of the RX path where shared SKBs might > happen. You're right, I misinterpreted what's happening here. My misunderstanding was that this was a situation where normal IPV4 input processing makes sure the SKB is unshared, and we had special code paths that didn't make sure that was the case. Rather, here, we have a special entrypoint for macvlan and AF_PACKET which is supposed to take care of such issues since it is known to execute in a different kind of environment. I'm pretty sure I'll apply this, after I check a few more things, thanks Johannes! -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
