From: Andrea Arcangeli <aarcange@redhat.com>
To: Michel Lespinasse <walken@google.com>
Cc: linux-mm@kvack.org, riel@redhat.com, peterz@infradead.org,
hughd@google.com, daniel.santos@pobox.com,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Subject: Re: [PATCH 2/7] mm: fix potential anon_vma locking issue in mprotect()
Date: Wed, 5 Sep 2012 00:16:41 +0200 [thread overview]
Message-ID: <20120904221641.GL3334@redhat.com> (raw)
In-Reply-To: <20120904215347.GA6769@google.com>
On Tue, Sep 04, 2012 at 02:53:47PM -0700, Michel Lespinasse wrote:
> I think the minimal fix would actually be:
>
> if (vma->anon_vma && (importer || start != vma->vm_start)) {
> anon_vma = vma->anon_vma;
> + else if (next->anon_vma && adjust_next)
> + anon_vma = next->anon_vma;
Right indeed. The last change required to the above is to check
adjust_next first.
> I suppose if we were to consider adding this fix to the stable series,
> we should probably do it in such a minimal way. I hadn't actually
> considered it, because I was only thinking about this patch series,
> and at patch 4/7 it becomes necessary to lock the anon_vma even if
> only the vm_end side gets modified (so we'd still end up with what I
> proposed in the end)
Ah, that fully explains you removed the optimization :). I was
reviewing the patch as a bugfix for upstream without noticing the
new requirements introduced by the later patches.
I would suggest to do the strict fix as above in as patch 1/8 and push
it in -mm, and to do only the optimization removal in 3/8. I think
we want it in -stable too later, so it'll make life easier to
cherry-pick the commit if it's merged independently.
Thanks!
Andrea
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WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Michel Lespinasse <walken@google.com>
Cc: linux-mm@kvack.org, riel@redhat.com, peterz@infradead.org,
hughd@google.com, daniel.santos@pobox.com,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Subject: Re: [PATCH 2/7] mm: fix potential anon_vma locking issue in mprotect()
Date: Wed, 5 Sep 2012 00:16:41 +0200 [thread overview]
Message-ID: <20120904221641.GL3334@redhat.com> (raw)
In-Reply-To: <20120904215347.GA6769@google.com>
On Tue, Sep 04, 2012 at 02:53:47PM -0700, Michel Lespinasse wrote:
> I think the minimal fix would actually be:
>
> if (vma->anon_vma && (importer || start != vma->vm_start)) {
> anon_vma = vma->anon_vma;
> + else if (next->anon_vma && adjust_next)
> + anon_vma = next->anon_vma;
Right indeed. The last change required to the above is to check
adjust_next first.
> I suppose if we were to consider adding this fix to the stable series,
> we should probably do it in such a minimal way. I hadn't actually
> considered it, because I was only thinking about this patch series,
> and at patch 4/7 it becomes necessary to lock the anon_vma even if
> only the vm_end side gets modified (so we'd still end up with what I
> proposed in the end)
Ah, that fully explains you removed the optimization :). I was
reviewing the patch as a bugfix for upstream without noticing the
new requirements introduced by the later patches.
I would suggest to do the strict fix as above in as patch 1/8 and push
it in -mm, and to do only the optimization removal in 3/8. I think
we want it in -stable too later, so it'll make life easier to
cherry-pick the commit if it's merged independently.
Thanks!
Andrea
next prev parent reply other threads:[~2012-09-04 22:16 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-04 9:20 [PATCH 0/7] use interval trees for anon rmap Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 1/7] mm: interval tree updates Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
2012-09-07 22:13 ` Andrew Morton
2012-09-07 22:13 ` Andrew Morton
2012-09-07 22:29 ` Michel Lespinasse
2012-09-07 22:29 ` Michel Lespinasse
2012-09-07 22:55 ` Andrew Morton
2012-09-07 22:55 ` Andrew Morton
2012-09-07 23:26 ` Michel Lespinasse
2012-09-07 23:26 ` Michel Lespinasse
2012-09-08 4:45 ` Hillf Danton
2012-09-08 4:45 ` Hillf Danton
2012-09-07 23:26 ` Michel Lespinasse
2012-09-07 23:26 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 2/7] mm: fix potential anon_vma locking issue in mprotect() Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
2012-09-04 14:27 ` Andrea Arcangeli
2012-09-04 14:27 ` Andrea Arcangeli
2012-09-04 21:53 ` Michel Lespinasse
2012-09-04 21:53 ` Michel Lespinasse
2012-09-04 22:16 ` Andrea Arcangeli [this message]
2012-09-04 22:16 ` Andrea Arcangeli
2012-09-05 0:45 ` Michel Lespinasse
2012-09-05 0:45 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 3/7] mm anon rmap: remove anon_vma_moveto_tail Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 4/7] mm anon rmap: replace same_anon_vma linked list with an interval tree Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
2012-09-05 0:51 ` Michel Lespinasse
2012-09-05 0:51 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 5/7] mm rmap: remove vma_address check for address inside vma Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 6/7] mm: add CONFIG_DEBUG_VM_RB build option Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
2012-09-14 22:14 ` Sasha Levin
2012-09-14 22:14 ` Sasha Levin
2012-09-14 22:40 ` Sasha Levin
2012-09-14 22:40 ` Sasha Levin
2012-09-14 22:46 ` Michel Lespinasse
2012-09-14 22:46 ` Michel Lespinasse
2012-09-15 0:00 ` Michel Lespinasse
2012-09-15 0:00 ` Michel Lespinasse
2012-09-15 7:52 ` Jiri Slaby
2012-09-15 7:52 ` Jiri Slaby
2012-09-16 19:07 ` Hugh Dickins
2012-09-16 19:07 ` Hugh Dickins
2012-09-22 7:19 ` Jiri Slaby
2012-09-22 7:19 ` Jiri Slaby
2012-09-15 9:26 ` Sasha Levin
2012-09-15 9:26 ` Sasha Levin
2012-09-20 21:39 ` Fengguang Wu
2012-09-20 22:27 ` Hugh Dickins
2012-09-20 22:27 ` Hugh Dickins
2012-09-20 22:31 ` Fengguang Wu
2012-09-20 22:31 ` Fengguang Wu
2012-09-04 9:20 ` [PATCH 7/7] mm: avoid taking rmap locks in move_ptes() Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse
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