From: "H. Peter Anvin" <hpa@zytor.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-mtd@lists.infradead.org,
Sasha Levin <levinsasha928@gmail.com>,
Dave Jones <davej@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: mtd: kernel BUG at arch/x86/mm/pat.c:279!
Date: Sun, 09 Sep 2012 13:33:38 -0700 [thread overview]
Message-ID: <504CFD22.3050300@zytor.com> (raw)
In-Reply-To: <1347217472.2068.35.camel@shinybook.infradead.org>
On 09/09/2012 12:04 PM, David Woodhouse wrote:
> On Sun, 2012-09-09 at 09:56 -0700, H. Peter Anvin wrote:
>>
>>> So it should either be start=0xfffffffffffff000 end=0xffffffffffffffff
>>> or it should be start=0xfffffffffffff000 len=0x1000.
>>
>> I would strongly object to the former; that kind of inclusive ranges
>> breed a whole class of bugs by themselves.
>
> Another alternative that avoids overflow issues is to use a PFN rather
> than a byte address.
>
Except as a result of that logic have a bunch of places which either
have rounding errors in how they calculate PFNs, or they think they can
stick PFNs into 32-bit numbers. :(
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Sasha Levin <levinsasha928@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mtd@lists.infradead.org, linux-mm <linux-mm@kvack.org>,
Dave Jones <davej@redhat.com>
Subject: Re: mtd: kernel BUG at arch/x86/mm/pat.c:279!
Date: Sun, 09 Sep 2012 13:33:38 -0700 [thread overview]
Message-ID: <504CFD22.3050300@zytor.com> (raw)
In-Reply-To: <1347217472.2068.35.camel@shinybook.infradead.org>
On 09/09/2012 12:04 PM, David Woodhouse wrote:
> On Sun, 2012-09-09 at 09:56 -0700, H. Peter Anvin wrote:
>>
>>> So it should either be start=0xfffffffffffff000 end=0xffffffffffffffff
>>> or it should be start=0xfffffffffffff000 len=0x1000.
>>
>> I would strongly object to the former; that kind of inclusive ranges
>> breed a whole class of bugs by themselves.
>
> Another alternative that avoids overflow issues is to use a PFN rather
> than a byte address.
>
Except as a result of that logic have a bunch of places which either
have rounding errors in how they calculate PFNs, or they think they can
stick PFNs into 32-bit numbers. :(
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Sasha Levin <levinsasha928@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mtd@lists.infradead.org, linux-mm <linux-mm@kvack.org>,
Dave Jones <davej@redhat.com>
Subject: Re: mtd: kernel BUG at arch/x86/mm/pat.c:279!
Date: Sun, 09 Sep 2012 13:33:38 -0700 [thread overview]
Message-ID: <504CFD22.3050300@zytor.com> (raw)
In-Reply-To: <1347217472.2068.35.camel@shinybook.infradead.org>
On 09/09/2012 12:04 PM, David Woodhouse wrote:
> On Sun, 2012-09-09 at 09:56 -0700, H. Peter Anvin wrote:
>>
>>> So it should either be start=0xfffffffffffff000 end=0xffffffffffffffff
>>> or it should be start=0xfffffffffffff000 len=0x1000.
>>
>> I would strongly object to the former; that kind of inclusive ranges
>> breed a whole class of bugs by themselves.
>
> Another alternative that avoids overflow issues is to use a PFN rather
> than a byte address.
>
Except as a result of that logic have a bunch of places which either
have rounding errors in how they calculate PFNs, or they think they can
stick PFNs into 32-bit numbers. :(
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-09-09 20:33 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-29 8:48 mtd: kernel BUG at arch/x86/mm/pat.c:279! Sasha Levin
2012-06-29 8:48 ` Sasha Levin
2012-07-30 11:00 ` Sasha Levin
2012-07-30 11:00 ` Sasha Levin
2012-07-30 11:00 ` Sasha Levin
2012-09-07 16:55 ` Sasha Levin
2012-09-07 16:55 ` Sasha Levin
2012-09-07 16:55 ` Sasha Levin
2012-09-07 18:14 ` Linus Torvalds
2012-09-07 18:14 ` Linus Torvalds
2012-09-07 18:14 ` Linus Torvalds
2012-09-07 22:42 ` Suresh Siddha
2012-09-07 22:42 ` Suresh Siddha
2012-09-07 22:42 ` Suresh Siddha
2012-09-07 23:09 ` Linus Torvalds
2012-09-07 23:09 ` Linus Torvalds
2012-09-07 23:09 ` Linus Torvalds
2012-09-07 23:54 ` Suresh Siddha
2012-09-07 23:54 ` Suresh Siddha
2012-09-07 23:54 ` Suresh Siddha
2012-09-08 19:57 ` Linus Torvalds
2012-09-08 19:57 ` Linus Torvalds
2012-09-09 14:56 ` Suresh Siddha
2012-09-09 14:56 ` Suresh Siddha
2012-09-09 14:56 ` Suresh Siddha
2012-09-09 15:31 ` Linus Torvalds
2012-09-09 15:31 ` Linus Torvalds
2012-09-09 15:31 ` Linus Torvalds
2012-09-09 17:01 ` H. Peter Anvin
2012-09-09 17:01 ` H. Peter Anvin
2012-09-09 17:01 ` H. Peter Anvin
2012-09-12 10:50 ` Sasha Levin
2012-09-12 10:50 ` Sasha Levin
2012-09-12 10:50 ` Sasha Levin
2012-09-12 10:56 ` Sasha Levin
2012-09-12 10:56 ` Sasha Levin
2012-09-12 10:56 ` Sasha Levin
2012-09-28 9:00 ` Sasha Levin
2012-09-28 9:00 ` Sasha Levin
2012-09-28 9:00 ` Sasha Levin
2012-09-28 16:44 ` Linus Torvalds
2012-09-28 16:44 ` Linus Torvalds
2012-09-28 16:44 ` Linus Torvalds
2012-09-28 18:05 ` Artem Bityutskiy
2012-09-28 18:05 ` Artem Bityutskiy
2012-09-28 19:13 ` Linus Torvalds
2012-09-28 19:13 ` Linus Torvalds
2012-09-28 19:13 ` Linus Torvalds
2012-09-28 19:44 ` Sasha Levin
2012-09-28 19:44 ` Sasha Levin
2012-09-28 19:44 ` Sasha Levin
2012-09-28 19:04 ` David Woodhouse
2012-09-28 19:04 ` David Woodhouse
2012-09-28 19:15 ` richard -rw- weinberger
2012-09-28 19:15 ` richard -rw- weinberger
2012-09-28 19:15 ` richard -rw- weinberger
2012-09-28 19:18 ` richard -rw- weinberger
2012-09-28 19:18 ` richard -rw- weinberger
2012-09-28 19:18 ` richard -rw- weinberger
2012-09-29 16:11 ` David Woodhouse
2012-09-29 16:11 ` David Woodhouse
2012-09-29 16:34 ` David Woodhouse
2012-09-29 16:34 ` David Woodhouse
2012-09-09 16:56 ` H. Peter Anvin
2012-09-09 16:56 ` H. Peter Anvin
2012-09-09 16:56 ` H. Peter Anvin
2012-09-09 19:04 ` David Woodhouse
2012-09-09 19:04 ` David Woodhouse
2012-09-09 20:33 ` H. Peter Anvin [this message]
2012-09-09 20:33 ` H. Peter Anvin
2012-09-09 20:33 ` H. Peter Anvin
2012-09-10 5:17 ` Sasha Levin
2012-09-10 5:17 ` Sasha Levin
2012-09-10 5:17 ` Sasha Levin
2012-09-08 8:10 ` Sasha Levin
2012-09-08 8:10 ` Sasha Levin
2012-09-08 8:10 ` Sasha Levin
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