From: Andrea Arcangeli <andrea@suse.de>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matthew Wilcox <willy@debian.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Andrew Morton <akpm@osdl.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>, Ben LaHaise <bcrl@kvack.org>,
linux-mm@kvack.org,
Architectures Group <linux-arch@vger.kernel.org>
Subject: Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE
Date: Wed, 26 May 2004 09:06:17 +0200 [thread overview]
Message-ID: <20040526070617.GN29378@dualathlon.random> (raw)
In-Reply-To: <Pine.LNX.4.58.0405251924360.15534@ppc970.osdl.org>
On Tue, May 25, 2004 at 07:26:21PM -0700, Linus Torvalds wrote:
> You're reading it wrong.
>
> The "including when the present flag is set to zero" part does not mean
> that the present flag was zero _before_, it means "is being set to zero"
> as in "having been non-zero before that".
"having been non-zero before that" makes a lot more sense indeed, the
wording in the specs wasn't the best IMHO. Interestingly the
ptep_establish at the end of handle_pte_fault would have hidden any
double fault completely, nobody but a tracer would have noticed that,
but it made very little sense that non-present entries can be cached.
It's all clear now thanks.
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <andrea@suse.de>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matthew Wilcox <willy@debian.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Andrew Morton <akpm@osdl.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>, Ben LaHaise <bcrl@kvack.org>,
linux-mm@kvack.org,
Architectures Group <linux-arch@vger.kernel.org>
Subject: Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE
Date: Wed, 26 May 2004 09:06:17 +0200 [thread overview]
Message-ID: <20040526070617.GN29378@dualathlon.random> (raw)
In-Reply-To: <Pine.LNX.4.58.0405251924360.15534@ppc970.osdl.org>
On Tue, May 25, 2004 at 07:26:21PM -0700, Linus Torvalds wrote:
> You're reading it wrong.
>
> The "including when the present flag is set to zero" part does not mean
> that the present flag was zero _before_, it means "is being set to zero"
> as in "having been non-zero before that".
"having been non-zero before that" makes a lot more sense indeed, the
wording in the specs wasn't the best IMHO. Interestingly the
ptep_establish at the end of handle_pte_fault would have hidden any
double fault completely, nobody but a tracer would have noticed that,
but it made very little sense that non-present entries can be cached.
It's all clear now thanks.
--
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next prev parent reply other threads:[~2004-05-26 7:06 UTC|newest]
Thread overview: 153+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-24 3:29 [PATCH] ppc64: Fix possible race with set_pte on a present PTE Benjamin Herrenschmidt
2004-05-24 3:47 ` Linus Torvalds
2004-05-24 4:13 ` Benjamin Herrenschmidt
2004-05-24 4:36 ` Linus Torvalds
2004-05-24 4:44 ` Benjamin Herrenschmidt
2004-05-24 5:10 ` Linus Torvalds
2004-05-24 5:10 ` Linus Torvalds
2004-05-24 5:34 ` Benjamin Herrenschmidt
2004-05-24 5:34 ` Benjamin Herrenschmidt
2004-05-24 5:38 ` Benjamin Herrenschmidt
2004-05-24 5:38 ` Benjamin Herrenschmidt
2004-05-24 5:52 ` Benjamin Herrenschmidt
2004-05-24 5:52 ` Benjamin Herrenschmidt
2004-05-24 7:39 ` Ingo Molnar
2004-05-24 7:39 ` Ingo Molnar
2004-05-24 5:39 ` Benjamin Herrenschmidt
2004-05-24 5:39 ` Benjamin Herrenschmidt
2004-05-25 3:43 ` Andrea Arcangeli
2004-05-25 3:43 ` Andrea Arcangeli
2004-05-25 4:00 ` Linus Torvalds
2004-05-25 4:00 ` Linus Torvalds
2004-05-25 4:17 ` Benjamin Herrenschmidt
2004-05-25 4:17 ` Benjamin Herrenschmidt
2004-05-25 4:37 ` Andrea Arcangeli
2004-05-25 4:37 ` Andrea Arcangeli
2004-05-25 4:40 ` Benjamin Herrenschmidt
2004-05-25 4:40 ` Benjamin Herrenschmidt
2004-05-25 4:20 ` Andrea Arcangeli
2004-05-25 4:20 ` Andrea Arcangeli
2004-05-25 4:39 ` Linus Torvalds
2004-05-25 4:39 ` Linus Torvalds
2004-05-25 4:44 ` Linus Torvalds
2004-05-25 4:44 ` Linus Torvalds
2004-05-25 4:59 ` Andrea Arcangeli
2004-05-25 4:59 ` Andrea Arcangeli
2004-05-25 5:09 ` Andrea Arcangeli
2004-05-25 5:09 ` Andrea Arcangeli
2004-05-25 4:50 ` Andrea Arcangeli
2004-05-25 4:50 ` Andrea Arcangeli
2004-05-25 4:59 ` Linus Torvalds
2004-05-25 4:59 ` Linus Torvalds
2004-05-25 4:43 ` David Mosberger
2004-05-25 4:43 ` David Mosberger
2004-05-25 4:53 ` Andrea Arcangeli
2004-05-25 4:53 ` Andrea Arcangeli
2004-05-27 21:56 ` David Mosberger
2004-05-27 21:56 ` David Mosberger
2004-05-27 22:00 ` Benjamin Herrenschmidt
2004-05-27 22:00 ` Benjamin Herrenschmidt
2004-05-27 22:12 ` David Mosberger
2004-05-27 22:12 ` David Mosberger
2004-05-25 11:44 ` Matthew Wilcox
2004-05-25 11:44 ` Matthew Wilcox
2004-05-25 14:48 ` Linus Torvalds
2004-05-25 14:48 ` Linus Torvalds
2004-05-25 15:35 ` Keith M Wesolowski
2004-05-25 15:35 ` Keith M Wesolowski
2004-05-25 16:19 ` Linus Torvalds
2004-05-25 16:19 ` Linus Torvalds
2004-05-25 17:25 ` David S. Miller
2004-05-25 17:25 ` David S. Miller
2004-05-25 17:49 ` Linus Torvalds
2004-05-25 17:49 ` Linus Torvalds
2004-05-25 17:54 ` David S. Miller
2004-05-25 17:54 ` David S. Miller
2004-05-25 18:05 ` Linus Torvalds
2004-05-25 18:05 ` Linus Torvalds
2004-05-25 20:30 ` Linus Torvalds
2004-05-25 20:30 ` Linus Torvalds
2004-05-25 20:35 ` David S. Miller
2004-05-25 20:35 ` David S. Miller
2004-05-25 20:35 ` David S. Miller
2004-05-25 20:49 ` Linus Torvalds
2004-05-25 20:49 ` Linus Torvalds
2004-05-25 20:57 ` David S. Miller
2004-05-25 20:57 ` David S. Miller
2004-05-26 6:20 ` Keith M Wesolowski
2004-05-26 6:20 ` Keith M Wesolowski
2004-05-25 21:40 ` Benjamin Herrenschmidt
2004-05-25 21:40 ` Benjamin Herrenschmidt
2004-05-25 21:54 ` Linus Torvalds
2004-05-25 21:54 ` Linus Torvalds
2004-05-25 22:00 ` Linus Torvalds
2004-05-25 22:00 ` Linus Torvalds
2004-05-25 22:07 ` Benjamin Herrenschmidt
2004-05-25 22:07 ` Benjamin Herrenschmidt
2004-05-25 22:14 ` Linus Torvalds
2004-05-25 22:14 ` Linus Torvalds
2004-05-26 0:21 ` Benjamin Herrenschmidt
2004-05-26 0:21 ` Benjamin Herrenschmidt
2004-05-26 0:50 ` Linus Torvalds
2004-05-26 0:50 ` Linus Torvalds
2004-05-26 3:25 ` Benjamin Herrenschmidt
2004-05-26 3:25 ` Benjamin Herrenschmidt
2004-05-26 4:08 ` Linus Torvalds
2004-05-26 4:08 ` Linus Torvalds
2004-05-26 4:12 ` Benjamin Herrenschmidt
2004-05-26 4:12 ` Benjamin Herrenschmidt
2004-05-26 4:18 ` Benjamin Herrenschmidt
2004-05-26 4:18 ` Benjamin Herrenschmidt
2004-05-26 4:50 ` Linus Torvalds
2004-05-26 4:50 ` Linus Torvalds
2004-05-26 4:49 ` Benjamin Herrenschmidt
2004-05-26 4:49 ` Benjamin Herrenschmidt
2004-05-26 4:28 ` Linus Torvalds
2004-05-26 4:28 ` Linus Torvalds
2004-05-26 4:46 ` Benjamin Herrenschmidt
2004-05-26 4:46 ` Benjamin Herrenschmidt
2004-05-26 4:54 ` Linus Torvalds
2004-05-26 4:54 ` Linus Torvalds
2004-05-26 4:55 ` Benjamin Herrenschmidt
2004-05-26 4:55 ` Benjamin Herrenschmidt
2004-05-26 5:41 ` Benjamin Herrenschmidt
2004-05-26 5:41 ` Benjamin Herrenschmidt
2004-05-26 5:59 ` [PATCH] (signoff) " Benjamin Herrenschmidt
2004-05-26 5:59 ` Benjamin Herrenschmidt
2004-05-26 6:55 ` Benjamin Herrenschmidt
2004-05-26 6:55 ` Benjamin Herrenschmidt
2004-05-26 7:11 ` [PATCH] ppc32 implementation of ptep_set_access_flags Benjamin Herrenschmidt
2004-05-26 15:22 ` Linus Torvalds
2004-05-26 18:49 ` David S. Miller
2004-05-26 21:43 ` Benjamin Herrenschmidt
2004-05-28 1:29 ` David Mosberger
2004-05-25 22:05 ` [PATCH] ppc64: Fix possible race with set_pte on a present PTE Benjamin Herrenschmidt
2004-05-25 22:05 ` Benjamin Herrenschmidt
2004-05-25 22:09 ` Linus Torvalds
2004-05-25 22:09 ` Linus Torvalds
2004-05-25 22:19 ` Benjamin Herrenschmidt
2004-05-25 22:19 ` Benjamin Herrenschmidt
2004-05-25 22:24 ` Linus Torvalds
2004-05-25 22:24 ` Linus Torvalds
2004-05-25 21:27 ` Andrea Arcangeli
2004-05-25 21:27 ` Andrea Arcangeli
2004-05-25 21:43 ` Linus Torvalds
2004-05-25 21:43 ` Linus Torvalds
2004-05-25 21:55 ` Andrea Arcangeli
2004-05-25 21:55 ` Andrea Arcangeli
2004-05-25 22:01 ` Linus Torvalds
2004-05-25 22:01 ` Linus Torvalds
2004-05-25 22:18 ` Ivan Kokshaysky
2004-05-25 22:18 ` Ivan Kokshaysky
2004-05-25 22:42 ` Andrea Arcangeli
2004-05-25 22:42 ` Andrea Arcangeli
2004-05-26 2:26 ` Linus Torvalds
2004-05-26 2:26 ` Linus Torvalds
2004-05-26 7:06 ` Andrea Arcangeli [this message]
2004-05-26 7:06 ` Andrea Arcangeli
2004-05-25 21:44 ` Andrea Arcangeli
2004-05-25 21:44 ` Andrea Arcangeli
-- strict thread matches above, loose matches on Subject: below --
2004-06-01 12:04 Martin Schwidefsky
2004-06-01 12:04 ` Martin Schwidefsky
2004-06-01 12:10 Martin Schwidefsky
2004-06-01 12:10 ` Martin Schwidefsky
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