linux-kernel - Re: [PATCH 1/9] x86, pkeys: add fault handling for PF

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Date:	Thu, 7 Jul 2016 15:40:27 +0100
From:	Mel Gorman <mgorman@...hsingularity.net>
To:	Dave Hansen <dave@...1.net>
Cc:	linux-kernel@...r.kernel.org, x86@...nel.org,
	linux-api@...r.kernel.org, linux-arch@...r.kernel.org,
	linux-mm@...ck.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, dave.hansen@...ux.intel.com,
	arnd@...db.de, hughd@...gle.com, viro@...iv.linux.org.uk
Subject: Re: [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault
 bit

On Thu, Jul 07, 2016 at 05:47:20AM -0700, Dave Hansen wrote:
> 
> From: Dave Hansen <dave.hansen@...ux.intel.com>
> 
> PF_PK means that a memory access violated the protection key
> access restrictions.  It is unconditionally an access_error()
> because the permissions set on the VMA don't matter (the PKRU
> value overrides it), and we never "resolve" PK faults (like
> how a COW can "resolve write fault).
> 
> Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>

An access fault gets propgated as SEGV_PKUERR. What happens if glibc
does not recognise it?

-- 
Mel Gorman
SUSE Labs