Re: [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit

From
Dave Hansen <hidden>
Date
2016-07-07 15:42:25
Also in
linux-arch, linux-mm, lkml
Reply to
Mel Gorman, 2016-07-07
On 07/07/2016 07:40 AM, Mel Gorman wrote:
On Thu, Jul 07, 2016 at 05:47:20AM -0700, Dave Hansen wrote:
quoted
From: Dave Hansen <dave.hansen@linux.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@linux.intel.com>
An access fault gets propgated as SEGV_PKUERR. What happens if glibc
does not recognise it?
It passes it through to the handler without any side-effects.  I don't
think it does anything differently with SEGV_* codes that it knows about
vs. unknown ones.  The only negative side-effect that I can think of is
that it won't have a nice error message for it.

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Thread (45 messages) 45 messages, 6 authors, last reply 2016-07-18
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