Re: PROBLEM: network data corruption (bisected to e5a4b0bb803b)

[Al Viro]

On Wed, Jul 27, 2016 at 08:26:48PM -0400, alexmcwhirter@xxxxxxxxxx wrote:

> I'm going to go ahead and say this is where my issue and the op's issue
> begin to branch apart from one another. He's seeing this on all incoming
> data, whereas i am only seeing it on ssl data and not on sun4v.
> 
> At this point i would say data from my issue is only going to cloud this
> issue as they seem to be two completely different issues revolving around
> the same commit. If i come across any relevant data for x86_64 ill be sure
> to post it if this isn't resolved by then, but for now i'm going to refrain
> from submitting anything sparc related.

Which just might mean that we have *three* issues here -
	(1) buggered __copy_to_user_inatomic() (and friends) on some sparcs
	(2) your ssl-only corruption
	(3) Alan's x86_64 corruption on plain TCP read - no ssl *or* sparc
anywhere, and no multi-segment recvmsg().  Which would strongly argue in
favour of some kind of copy_page_to_iter() breakage triggered when handling
a fragmented skb, as in (1).  Except that I don't see anything similar in
x86_64 uaccess primitives...