From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>, Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Al Viro <viro@zeniv.linux.org.uk>, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
Michel Lespinasse <walken@google.com>,
Kirill A Shutemov <kirill.shutemov@linux.intel.com>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/4] mm: migrate: Close race between migration completion and mprotect
Date: Thu, 02 Oct 2014 11:48:56 -0400 [thread overview]
Message-ID: <542D73E8.5060307@redhat.com> (raw)
In-Reply-To: <1412256558-9995-3-git-send-email-mgorman@suse.de>
On 10/02/2014 09:29 AM, Mel Gorman wrote:
> A migration entry is marked as write if pte_write was true at the time the
> entry was created. The VMA protections are not double checked when migration
> entries are being removed as mprotect marks write-migration-entries as
> read. It means that potentially we take a spurious fault to mark PTEs write
> again but it's straight-forward. However, there is a race between write
> migrations being marked read and migrations finishing. This potentially
> allows a PTE to be write that should have been read. Close this race by
> double checking the VMA permissions when migration completes.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
next prev parent reply other threads:[~2014-10-02 15:51 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-02 13:29 [PATCH 0/4] NUMA balancing related fixlets Mel Gorman
2014-10-02 13:29 ` [PATCH 1/4] mm: remove misleading ARCH_USES_NUMA_PROT_NONE (from Andrew's tree) Mel Gorman
2014-10-02 13:29 ` [PATCH 2/4] mm: migrate: Close race between migration completion and mprotect Mel Gorman
2014-10-02 15:48 ` Rik van Riel [this message]
2014-10-02 16:41 ` Linus Torvalds
2014-10-02 13:29 ` [PATCH 3/4] mm: mempolicy: Skip inaccessible VMAs when setting MPOL_MF_LAZY Mel Gorman
2014-10-02 15:51 ` Rik van Riel
2014-10-02 13:29 ` [PATCH 4/4] mm: numa: Do not mark PTEs pte_numa when splitting huge pages Mel Gorman
2014-10-02 15:18 ` Kirill A. Shutemov
2014-10-02 16:19 ` Rik van Riel
2014-10-02 16:36 ` Linus Torvalds
2014-10-02 18:58 ` Sasha Levin
2014-10-02 19:03 ` Linus Torvalds
2014-10-02 19:07 ` Kirill A. Shutemov
2014-10-02 19:12 ` Sasha Levin
2014-10-02 19:26 ` Linus Torvalds
2014-10-02 19:28 ` Rik van Riel
2014-10-02 19:32 ` Linus Torvalds
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