Subject: Re: [PATCH] [v4] x86, pkeys: fix siginfo ABI breakage from new field

From: Ingo Molnar <[email-masked]>
Date: Thu, 3 Mar 2016 16:41:04 +0100

* Dave Hansen <[email-masked]> wrote:

> To fix this, we replace the u64 with an '__u32'.  The __u32 is guaranteed to 
> union well with the pointers from _addr_bnd.  It is also plenty large enough to 
> store the 16-bit pkey we have today on x86.

The 'union well' sentence is really a leftover from the earlier changelog (the 
problem was never about interaction between union members) - a better explantion 
is:

> To fix this, we replace the u64 with an '__u32'.  The __u32 does not change the 
> minimum alignment requirements of the structure and it is also plenty large 
> enough to store the 16-bit pkey we have today on x86.

I fixed this up locally, no need to resend.

Thanks,

	Ingo