From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Greg Edwards <edwardsg@sgi.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
Linus Torvalds <torvalds@osdl.org>,
Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>, Jack Steiner <steiner@sgi.com>
Subject: Re: [PATCH] Fix mmap_kmem (was: [question] What's the difference between /dev/kmem and /dev/mem)
Date: Wed, 17 Aug 2005 00:33:45 +0100 [thread overview]
Message-ID: <1124235225.25433.1.camel@localhost.localdomain> (raw)
In-Reply-To: <20050816221223.GA9991@sgi.com>
On Maw, 2005-08-16 at 17:12 -0500, Greg Edwards wrote:
> mmap_mem suffers from a lack of proper checks as well. For example, on
> Altix page 0 of each node is reserved for prom and a read or write to it
> will cause an MCA. mmaping /dev/mem with offset 0 will nicely explode.
> Would adding a pfn_valid test in mmap_mem be the best bet, or could we
> consolidate the checks currently in mmap_kmem into mmap_mem?
If you use /dev/mem you should know what you are doing. Even with
"checks" dd if=/dev/zero of=/dev/mem will do bad things. Trapping
obviously bad cases is fine, but complete sanity checking may actually
be counter productive.
next prev parent reply other threads:[~2005-08-16 23:07 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-11 21:36 [question] What's the difference between /dev/kmem and /dev/mem Steven Rostedt
2005-08-12 1:15 ` [PATCH] Fix mmap_kmem (was: [question] What's the difference between /dev/kmem and /dev/mem) Steven Rostedt
2005-08-12 14:25 ` Hugh Dickins
2005-08-12 16:35 ` Linus Torvalds
2005-08-12 16:56 ` Dave Jones
2005-08-12 17:07 ` Steven Rostedt
2005-08-12 17:16 ` Arjan van de Ven
2005-08-12 17:32 ` Steven Rostedt
2005-08-12 17:01 ` Steven Rostedt
2005-08-13 13:39 ` [PATCH] Fix mmap kmem " Nicolas George
2005-08-13 16:50 ` [PATCH] Fix mmap_kmem " Arjan van de Ven
2005-08-13 16:56 ` Linus Torvalds
2005-08-13 17:25 ` Arjan van de Ven
2005-08-13 17:37 ` Linus Torvalds
2005-08-13 18:18 ` Arjan van de Ven
2005-08-16 22:12 ` Greg Edwards
2005-08-16 23:33 ` Alan Cox [this message]
2005-08-16 23:47 ` Steven Rostedt
2005-08-15 19:33 ` Olaf Hering
2005-08-15 21:14 ` Jeff Dike
2005-08-15 21:50 ` Olaf Hering
2005-08-15 22:41 ` Linus Torvalds
2005-08-16 1:16 ` Steven Rostedt
2005-08-16 1:22 ` Steven Rostedt
2005-08-16 1:36 ` Linus Torvalds
2005-08-13 16:57 ` Joshua Hudson
2005-08-13 17:27 ` Arjan van de Ven
2005-08-14 14:50 ` Martin J. Bligh
2005-08-18 14:07 ` Arjan van de Ven
2005-08-18 14:18 ` Steven Rostedt
[not found] <1123796188.17269.127.camel@localhost.localdomain.suse.lists.linux.kernel>
[not found] ` <1123809302.17269.139.camel@localhost.localdomain.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.58.0508120930150.3295@g5.osdl.org.suse.lists.linux.kernel>
2005-08-12 16:54 ` Andi Kleen
2005-08-12 17:56 ` Arjan van de Ven
2005-08-12 18:26 ` Andi Kleen
2005-08-13 9:56 ` Ingo Oeser
2005-08-13 12:40 ` Andi Kleen
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