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Date:   Wed, 15 Nov 2023 14:38:12 +0530
From:   Yuran Pereira <yuran.pereira@hotmail.com>
To:     Danilo Krummrich <dakr@redhat.com>
Cc:     airlied@gmail.com, kherbst@redhat.com, lyude@redhat.com,
        daniel@ffwll.ch, sumit.semwal@linaro.org, christian.koenig@amd.com,
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Subject: Re: [PATCH] drm/nouveau: Prevents NULL pointer dereference in
 nouveau_uvmm_sm_prepare
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Hello Danilo,
On Tue, Nov 14, 2023 at 05:23:59PM +0100, Danilo Krummrich wrote:
> Hi Yuran,
> 
> op_map_prepare() can't be called with `args` being NULL, since when called
> through nouveau_uvmm_sm_unmap_prepare() we can't hit the DRM_GPUVA_OP_MAP
> case at all.
> 
> Unmapping something never leads to a new mapping being created, it can lead
> to remaps though.
> 
Yes, you're right. I certainly hadn't noticed that when I first
submitted this patch.
> 
> This check is not required for the reason given above. If you like, you
> can change this patch up to remove the args check and add a comment like:
> 
> /* args can't be NULL when called for a map operation. */
> 
Sure, I'll do that, sounds reasonable.

Thank you for your feedback.

Yuran
> 
> Yeah, I see how this unnecessary check made you think so.
> 
> - Danilo
> 
>