From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Kyle McMartin <kyle@infradead.org>
Cc: John David Anglin <dave@hiauly1.hia.nrc.ca>,
deller@gmx.de, linux-parisc@vger.kernel.org
Subject: Re: [PATCH] [RFC] fix kernel crash (protection id trap) when
Date: Mon, 22 Dec 2008 16:46:30 -0600 [thread overview]
Message-ID: <1229985990.3345.47.camel@localhost.localdomain> (raw)
In-Reply-To: <20081221222005.GB30144@bombadil.infradead.org>
On Sun, 2008-12-21 at 17:20 -0500, Kyle McMartin wrote:
> On Sun, Dec 21, 2008 at 10:20:16AM -0500, John David Anglin wrote:
> > > Honestly, I can't decide whether to apply this. It really should never
> > > happen in the kernel, since the kernel can guarantee it won't get the
> > > access rights failure (highest privilege level, and can set %sr and
> > > %protid to whatever it wants.)
> >
> > I believe this change should be applied because we enable P and the
> > hardware can generate the exception. Yes, it should never happen, but
> > the coding to prevent this occurring is very subtle.
> >
>
> If we're going to paper over a bug like this, we might as well just turn
> the P-bit off...
I'm afraid you can't. The invisibility of the kernel space from user
space relies on this, as does quite a lot of the page protections.
James
next prev parent reply other threads:[~2008-12-22 22:46 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-17 22:46 [PATCH] [RFC] fix kernel crash (protection id trap) when compiling ruby1.9 Helge Deller
2008-12-18 0:05 ` [PATCH] [RFC] fix kernel crash (protection id trap) when compiling John David Anglin
2008-12-18 0:43 ` Kyle McMartin
2008-12-18 3:02 ` [PATCH] [RFC] fix kernel crash (protection id trap) when John David Anglin
2008-12-18 3:05 ` Kyle McMartin
2008-12-18 4:04 ` Kyle McMartin
2008-12-18 16:16 ` Carlos O'Donell
2008-12-18 18:28 ` Kyle McMartin
2008-12-19 15:25 ` Carlos O'Donell
2008-12-19 16:13 ` John David Anglin
2008-12-19 16:23 ` Carlos O'Donell
2008-12-19 16:28 ` Kyle McMartin
2008-12-19 16:35 ` Carlos O'Donell
2008-12-19 16:36 ` Carlos O'Donell
2008-12-19 16:44 ` Kyle McMartin
2008-12-19 17:28 ` Carlos O'Donell
2008-12-19 17:33 ` Kyle McMartin
2008-12-19 17:36 ` Carlos O'Donell
2008-12-19 17:39 ` Kyle McMartin
2008-12-19 17:42 ` Kyle McMartin
2008-12-19 18:43 ` Carlos O'Donell
2008-12-18 1:46 ` [PATCH] [RFC] fix kernel crash (protection id trap) when compiling ruby1.9 Carlos O'Donell
2008-12-18 2:02 ` Carlos O'Donell
2008-12-18 13:13 ` Helge Deller
2008-12-18 15:28 ` [PATCH] [RFC] fix kernel crash (protection id trap) when compiling John David Anglin
2008-12-18 16:09 ` Carlos O'Donell
2008-12-18 2:36 ` [PATCH] [RFC] fix kernel crash (protection id trap) when compiling ruby1.9 Kyle McMartin
2008-12-18 12:21 ` Carlos O'Donell
2008-12-18 7:03 ` Kyle McMartin
2008-12-18 13:09 ` Helge Deller
2008-12-18 15:05 ` Kyle McMartin
2008-12-19 21:29 ` Kyle McMartin
2008-12-19 22:59 ` Helge Deller
2008-12-19 23:34 ` Kyle McMartin
2008-12-20 17:07 ` [PATCH] [RFC] fix kernel crash (protection id trap) when John David Anglin
2008-12-21 15:20 ` John David Anglin
2008-12-21 17:27 ` John David Anglin
2008-12-21 21:33 ` Kyle McMartin
2008-12-21 22:02 ` Kyle McMartin
2008-12-21 22:52 ` John David Anglin
2008-12-21 22:11 ` John David Anglin
2008-12-21 22:52 ` Helge Deller
2008-12-21 22:58 ` John David Anglin
2008-12-21 23:08 ` Helge Deller
2008-12-22 0:07 ` John David Anglin
2008-12-22 22:43 ` James Bottomley
2008-12-22 22:46 ` Kyle McMartin
2008-12-23 2:31 ` John David Anglin
2008-12-23 2:54 ` Kyle McMartin
2008-12-23 3:15 ` John David Anglin
2008-12-23 13:13 ` John David Anglin
2008-12-21 22:20 ` Kyle McMartin
2008-12-21 22:48 ` John David Anglin
2008-12-22 22:46 ` James Bottomley [this message]
2008-12-22 22:47 ` Kyle McMartin
2008-12-21 22:59 ` Helge Deller
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