linux-kernel - Re: [PATCH] sysfs: Don't block indefinitely for unmapped files.

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Message-ID: <49A50C63.8040302@gmail.com>
Date:	Wed, 25 Feb 2009 18:16:19 +0900
From:	Tejun Heo <htejun@...il.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	Greg Kroah-Hartman <gregkh@...e.de>, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, Jesse Barnes <jbarnes@...tuousgeek.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] sysfs: Don't block indefinitely for unmapped files.

Hello, Eric.

Eric W. Biederman wrote:
> This patch modifies sysfs bin files so that we can remove
> the bin file while they are still mapped.  When the kobject
> is removed we unmap the bin file and arrange for future
> accesses to the mapping to receive SIGBUS.
> 
> Implementing this prevents a nasty DOS when pci devices are
> hot plugged and unplugged.  Where if any of their resources
> were mmaped the kernel could not free up their pci resources
> or release their pci data structures.
>
> Signed-off-by: Eric W. Biederman <ebiederm@...stanetworks.com>

Heh... this is so cool.  I've never thought about it.  I would really
like more comments but other than that

Acked-by: Tejun Heo <tj@...nel.org>

-- 
tejun
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