----- Original Message Follows ----- From: Ben Hutchings <[email protected]> To: Greg KH <[email protected]> Cc: [email protected], [email protected], Don Skidmore <[email protected]>, Milton Miller <[email protected]>, "David S. Miller" <[email protected]>, Anton Blanchard <[email protected]>, [email protected], [email protected], [email protected], [email protected], Jeff Kirsher <[email protected]> Subject: Re: [Stable-review] [22/68] ixgbe: prevent speculative processing of descriptors before ready Date: Tue, 01 Mar 2011 02:14:33 +0000
> On Mon, 2011-02-28 at 08:22 -0800, Greg KH wrote: > > 2.6.32-longterm review patch. If anyone has any > > objections, please let us know. > > ------------------ > > > > From: Milton Miller <[email protected]> > > > > commit 3c945e5b3719bcc18c6ddd31bbcae8ef94f3d19a > > upstream. > > The PowerPC architecture does not require loads to > > independent bytes to be ordered without adding an > > explicit barrier. > > In ixgbe_clean_rx_irq we load the status bit then load > > the packet data. With packet split disabled if these > > loads go out of order we get a stale packet, but we will > > notice the bad sequence numbers and drop it. > > The problem occurs with packet split enabled where the > > TCP/IP header and data are in different descriptors. If > > the reads go out of order we may have data that doesn't > match the TCP/IP header. Since we use hardware > > checksumming this bad data is never verified and it > makes it all the way to the application. [...] > > Packet splitting should be completely disabled on the > 82599, anyway. Greg, what happened to this patch: This was initially observed on 82598 and is still needed there. milton _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
