linux-kernel - Re: [PATCH, RESEND] xen: allocate gntdev_copy

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Date:	Fri, 26 Feb 2016 08:44:11 -0500
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	Arnd Bergmann <arnd@...db.de>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	David Vrabel <david.vrabel@...rix.com>
Cc:	linux-arm-kernel@...ts.infradead.org,
	xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH, RESEND] xen: allocate gntdev_copy_batch dynamically

On 02/25/2016 04:25 PM, Arnd Bergmann wrote:
> struct gntdev_copy_batch is arguably too large to fit on the kernel stack,
> and we get a warning about the stack usage in gntdev_ioctl_grant_copy:
>
> drivers/xen/gntdev.c:949:1: error: the frame size of 1240 bytes is larger than 1024 bytes
>
> This changes the code to us a dynamic allocation instead.
>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> Fixes: a4cdb556cae0 ("xen/gntdev: add ioctl for grant copy")
> ---
>   drivers/xen/gntdev.c | 17 ++++++++++-------
>   1 file changed, 10 insertions(+), 7 deletions(-)
>
> I sent this in January, Boris sent an almost identical patch
> as http://www.gossamer-threads.com/lists/xen/devel/414056
> but the bug remains present in mainline and linux-next as of
> Feb 25.
>
> Could you apply one of the patches before the bug makes it
> into v4.5?

David wanted to shrink the structure size instead:
     http://www.gossamer-threads.com/lists/xen/devel/414535

-boris