[Intel-gfx] [PATCH] drm/i915: Use a temporary va_list for two-pass string handling

[Daniel Vetter]

On Fri, Sep 20, 2013 at 10:20:59AM +0100, Chris Wilson wrote:
> In
> 
> commit edc3d8848dc9fe2a470316363dab8ef211d77e01
> Author: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Date:   Thu May 23 13:55:35 2013 +0300
> 
>     drm/i915: avoid big kmallocs on reading error state
> 
> we introduce a two-pass mechanism for splitting long strings being
> formatted into the error-state. The first pass finds the length, and the
> second pass emits the right portion of the string into the accumulation
> buffer. Unfortunately we use the same va_list for both passes, resulting
> in the second pass reading garbage off the end of the argument list. As
> the two passes are only used for boundaries between read() calls, the
> corruption is only rarely seen.
> 
> This fixes the root cause behind
> 
> commit baf27f9b17bf2f369f3865e38c41d2163e8d815d
> Author: Chris Wilson <chris at chris-wilson.co.uk>
> Date:   Sat Jun 29 23:26:50 2013 +0100
> 
>     drm/i915: Break up the large vsnprintf() in print_error_buffers()
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: stable at vger.kernel.org

Picked up for -fixes, thanks for the patch.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch