All of lore.kernel.org
 help / color / mirror / Atom feed
From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.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>,
	dwmw2@infradead.org
Subject: Re: mtd: kernel BUG at arch/x86/mm/pat.c:279!
Date: Sun, 09 Sep 2012 09:56:17 -0700	[thread overview]
Message-ID: <504CCA31.2000003@zytor.com> (raw)
In-Reply-To: <CA+55aFzeKcV5hROLJE31dNi3SEs+s6o0LL=96Kh8QGHPx=aZnA@mail.gmail.com>

On 09/08/2012 12:57 PM, Linus Torvalds wrote:
>
> Ack.
>
> Anyway, that means that the BUG_ON() is likely bogus, but so is the
> whole calling convention.
>
> The 4kB range starting at 0xfffffffffffff000 sounds like a *valid*
> range, but that requires that we fix the calling convention to not
> have that "end" (exclusive) thing. It should either be "end"
> (inclusive), or just "len".
>

On x86, it is definitely NOT a valid range.  There is no physical 
addresses there, and there will never be any.

> 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.

	-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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
	Sasha Levin <levinsasha928@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	dwmw2@infradead.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 09:56:17 -0700	[thread overview]
Message-ID: <504CCA31.2000003@zytor.com> (raw)
In-Reply-To: <CA+55aFzeKcV5hROLJE31dNi3SEs+s6o0LL=96Kh8QGHPx=aZnA@mail.gmail.com>

On 09/08/2012 12:57 PM, Linus Torvalds wrote:
>
> Ack.
>
> Anyway, that means that the BUG_ON() is likely bogus, but so is the
> whole calling convention.
>
> The 4kB range starting at 0xfffffffffffff000 sounds like a *valid*
> range, but that requires that we fix the calling convention to not
> have that "end" (exclusive) thing. It should either be "end"
> (inclusive), or just "len".
>

On x86, it is definitely NOT a valid range.  There is no physical 
addresses there, and there will never be any.

> 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.

	-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
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
	Sasha Levin <levinsasha928@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	dwmw2@infradead.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 09:56:17 -0700	[thread overview]
Message-ID: <504CCA31.2000003@zytor.com> (raw)
In-Reply-To: <CA+55aFzeKcV5hROLJE31dNi3SEs+s6o0LL=96Kh8QGHPx=aZnA@mail.gmail.com>

On 09/08/2012 12:57 PM, Linus Torvalds wrote:
>
> Ack.
>
> Anyway, that means that the BUG_ON() is likely bogus, but so is the
> whole calling convention.
>
> The 4kB range starting at 0xfffffffffffff000 sounds like a *valid*
> range, but that requires that we fix the calling convention to not
> have that "end" (exclusive) thing. It should either be "end"
> (inclusive), or just "len".
>

On x86, it is definitely NOT a valid range.  There is no physical 
addresses there, and there will never be any.

> 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.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  parent reply	other threads:[~2012-09-09 16:57 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 [this message]
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
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=504CCA31.2000003@zytor.com \
    --to=hpa@zytor.com \
    --cc=akpm@linux-foundation.org \
    --cc=davej@redhat.com \
    --cc=dwmw2@infradead.org \
    --cc=levinsasha928@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=suresh.b.siddha@intel.com \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.