Messages in this thread | | | Date | Tue, 7 Oct 2014 16:17:02 +0200 | From | Lothar Waßmann <> | Subject | Re: [PATCH] net: fec: fix regression on i.MX28 introduced by rx_copybreak support |
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Hi,
David Laight wrote: > From: Lothar Waßmann > > commit 1b7bde6d659d ("net: fec: implement rx_copybreak to improve rx performance") > > introduced a regression for i.MX28. The swap_buffer() function doing > > the endian conversion of the received data on i.MX28 may access memory > > beyond the actual packet size in the DMA buffer. fec_enet_copybreak() > > does not copy those bytes, so that the last bytes of a packet may be > > filled with invalid data after swapping. > > This will likely lead to checksum errors on received packets. > > E.g. when trying to mount an NFS rootfs: > > UDP: bad checksum. From 192.168.1.225:111 to 192.168.100.73:44662 ulen 36 > > > > Do the byte swapping and copying to the new skb in one go if > > necessary. > > ISTM that if you need to do the 'swap' you should copy the data regardless > of the length. > The swap function has to look at at most 3 bytes beyond the actual packet length. That is what the original swap_buffer() function does and what the new function swap_buffer2(), that does the endian swapping while copying to the new buffer, also does.
Lothar Waßmann -- ___________________________________________________________
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