From: Christoph Lameter <cl@linux.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: fix hang on anon_vma->root->lock
Date: Fri, 27 Aug 2010 14:29:28 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1008271420400.18495@router.home> (raw)
In-Reply-To: <AANLkTi=FeHnLu4_6M5N6yUL==4YyxVXXxsccsE2kNUbm@mail.gmail.com>
On Fri, 27 Aug 2010, Hugh Dickins wrote:
> Eh? My solution was a second page_mapped(page) test i.e. testing an atomic.
Argh. Right. Looked like a global to me. Did not see the earlier local
def.
If you still use a pointer then what does insure that the root
pointer was not changed after the ACCESS_ONCE? The free semantics
of an anon_vma?
Since there is no lock taken before the mapped check none of the
earlier reads from the anon vma structure nor the page mapped check
necessarily reflect a single state of the anon_vma.
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next prev parent reply other threads:[~2010-08-27 19:29 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-26 6:12 Hugh Dickins
2010-08-26 6:41 ` David Miller
2010-08-26 10:54 ` Hugh Dickins
2010-08-26 19:00 ` David Miller
2010-08-27 0:19 ` Andrea Arcangeli
2010-08-26 13:32 ` Rik van Riel
2010-08-26 23:50 ` Andrea Arcangeli
2010-08-27 1:43 ` Hugh Dickins
2010-08-27 9:55 ` Andrea Arcangeli
2010-08-27 16:43 ` Hugh Dickins
2010-08-27 17:13 ` Christoph Lameter
2010-08-27 17:55 ` Hugh Dickins
2010-08-27 19:29 ` Christoph Lameter [this message]
2010-08-27 20:14 ` Hugh Dickins
2010-08-27 20:56 ` Christoph Lameter
2010-08-27 21:28 ` Hugh Dickins
2010-08-27 21:33 ` Hugh Dickins
2010-08-27 23:06 ` Christoph Lameter
2010-08-28 1:07 ` Hugh Dickins
2010-08-28 2:47 ` Christoph Lameter
2010-08-28 10:17 ` Peter Zijlstra
2010-08-28 15:54 ` Andrea Arcangeli
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