Re: [PATCH] msr: Fix NULL pointer deref due to msr_open onnonexistent CPUs

[Jonathan Corbet]

On Thu, 14 Aug 2008 15:43:33 -0700
"Darrick J. Wong" <djwong@xxxxxxxxxx> wrote:

> msr_open tests for someone trying to open a device for a nonexistent
> CPU. However, the function always returns 0, not ret like it should,
> hence userspace can BUG the kernel trivially.  This bug was
> introduced by the cdev lock_kernel pushdown patch last May.

> -	return 0;
> +	return ret;

Oops, that was pretty silly.  Apologies for the screwup.

jon
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