RE: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

From: Alexander Duyck > Sent: 01 February 2016 18:18 > >> 1) Unaligned accesses > > > > Remember the even if you do a 'realignment copy' of the IP header, > > at some point the 'userdata' of the packet has to be accessed. > > Mostly this will be with memcpy() and you want that copy to be aligned.

RE: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

From: David Miller > Sent: 31 January 2016 03:45 > To: alexander.du...@gmail.com ... > > I would really prefer to keep the pages DMA aligned, and the skb->data > > IP aligned. If nothing else it has the advantage of actually having > > the proper alignment on all the headers if I only pull the

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Mon, Feb 1, 2016 at 8:50 AM, David Laight wrote: > From: David Miller >> Sent: 31 January 2016 03:45 >> To: alexander.du...@gmail.com > ... >> > I would really prefer to keep the pages DMA aligned, and the skb->data >> > IP aligned. If nothing else it has the

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

From: Alexander Duyck Date: Sun, 31 Jan 2016 01:12:03 -0800 > If nothing else we can discuss this further in Seville as I am just > not convinced changing the drivers is the right way to go about fixing > this, and I won't have the time to really get around to doing

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On (01/31/16 11:17), David Miller wrote: > > > If nothing else we can discuss this further in Seville as I am just > > not convinced changing the drivers is the right way to go about fixing > > this, and I won't have the time to really get around to doing any of > > it until I have come back from

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Sat, Jan 30, 2016 at 7:45 PM, David Miller wrote: > From: Alexander Duyck > Date: Sat, 30 Jan 2016 17:13:35 -0800 > >> The NIC hardware only allows us to set receive buffer sizes in 1K >> increments. I think fm10k may be an exception in that it

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Sat, 2016-01-30 at 10:36 -0800, Alexander Duyck wrote: > As far as the NET_IP_ALIGN on the page offset I think it is a horrible > idea. Basically it means we have to allocate at least 1K more space > than we need since page sizes are powers of 2, and buffer sizes in > hardware are measured in

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Sat, Jan 30, 2016 at 8:17 AM, Sowmini Varadhan wrote: > On (01/29/16 19:23), Eric Dumazet wrote: >> BTW, even a memcpy(_addrs->v4addrs, >saddr, 8) could crash, as >> the compiler can certainly assume src and dst are 4 bytes aligned, and >> could use word accesses

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Sat, Jan 30, 2016 at 8:17 AM, Sowmini Varadhan wrote: > On (01/29/16 19:23), Eric Dumazet wrote: >> BTW, even a memcpy(_addrs->v4addrs, >saddr, 8) could crash, as >> the compiler can certainly assume src and dst are 4 bytes aligned, and >> could use word accesses

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On (01/30/16 09:43), Tom Herbert wrote: > That is not the only case, If a GRE TEB packet is ever received and > flow dissector is called for any reason (like skb_get_hash) there's > going to be problems-- and this doesn't require GRE to even be > configured on the host. > > I have a patch that

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On (01/29/16 19:23), Eric Dumazet wrote: > BTW, even a memcpy(_addrs->v4addrs, >saddr, 8) could crash, as > the compiler can certainly assume src and dst are 4 bytes aligned, and > could use word accesses when inlining memcpy() even on Sparc. > > Apparently the compiler used by Sowmini is gentle.

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Sat, Jan 30, 2016 at 11:26 AM, Eric Dumazet wrote: > On Sat, 2016-01-30 at 10:36 -0800, Alexander Duyck wrote: > >> As far as the NET_IP_ALIGN on the page offset I think it is a horrible >> idea. Basically it means we have to allocate at least 1K more space >> than we

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

From: Alexander Duyck Date: Sat, 30 Jan 2016 17:13:35 -0800 > The NIC hardware only allows us to set receive buffer sizes in 1K > increments. I think fm10k may be an exception in that it may be able > to support 512 byte, but otherwise igb and ixgbe are strictly set

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

From: Eric Dumazet Date: Fri, 29 Jan 2016 19:23:54 -0800 > On Fri, 2016-01-29 at 18:49 -0800, Alexander Duyck wrote: >> This patch fixes an issue with unaligned accesses when using >> eth_get_headlen on a page that was DMA aligned instead of being IP aligned. >> The fact

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Fri, 2016-01-29 at 18:49 -0800, Alexander Duyck wrote: > This patch fixes an issue with unaligned accesses when using > eth_get_headlen on a page that was DMA aligned instead of being IP aligned. > The fact is when trying to check the length we don't need to be looking at > the flow label so we

Re: [net PATCH] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen

On Fri, Jan 29, 2016 at 7:35 PM, David Miller wrote: > From: Eric Dumazet > Date: Fri, 29 Jan 2016 19:23:54 -0800 > >> On Fri, 2016-01-29 at 18:49 -0800, Alexander Duyck wrote: >>> This patch fixes an issue with unaligned accesses when using >>>