Re: FAILED: patch "[PATCH] drm/amd/display: fix double memory allocation" failed to apply to 6.3-stable tree

[Mario Limonciello <mlimonci@amd.com>]

On 5/13/23 02:20, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 6.3-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> To reproduce the conflict and resubmit, you may use the following commands:
> 
> git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.3.y
> git checkout FETCH_HEAD
> git cherry-pick -x f5442b35e69e42015ef3082008c0d85cdcc0ca05
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023051306-elves-dividers-01e7@gregkh' --subject-prefix 'PATCH 6.3.y' HEAD^..
> 
> Possible dependencies:
> 
> f5442b35e69e ("drm/amd/display: fix double memory allocation")
> b5006f873b99 ("drm/amd/display: initialize link_srv in virtual env")
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
>  From f5442b35e69e42015ef3082008c0d85cdcc0ca05 Mon Sep 17 00:00:00 2001
> From: Martin Leung <Martin.Leung@amd.com>
> Date: Tue, 14 Mar 2023 09:27:20 -0400
> Subject: [PATCH] drm/amd/display: fix double memory allocation
> 
> [Why & How]
> when trying to fix a nullptr dereference on VMs,
> accidentally doubly allocated memory for the non VM
> case. removed the extra link_srv creation since
> dc_construct_ctx is called in both VM and non VM cases
> Also added a proper fail check for if kzalloc fails
> 
> Cc: stable@vger.kernel.org
> Cc: Mario Limonciello <mario.limonciello@amd.com>
> Reviewed-by: Leo Ma <Hanghong.Ma@amd.com>
> Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
> Signed-off-by: Martin Leung <Martin.Leung@amd.com>
> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
> index 40f2e174c524..52564b93f7eb 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
> @@ -887,7 +887,10 @@ static bool dc_construct_ctx(struct dc *dc,
>   	}
>   
>   	dc->ctx = dc_ctx;
> +
>   	dc->link_srv = link_create_link_service();
> +	if (!dc->link_srv)
> +		return false;
>   
>   	return true;
>   }
> @@ -986,8 +989,6 @@ static bool dc_construct(struct dc *dc,
>   		goto fail;
>   	}
>   
> -	dc->link_srv = link_create_link_service();
> -
>   	dc->res_pool = dc_create_resource_pool(dc, init_params, dc_ctx->dce_version);
>   	if (!dc->res_pool)
>   		goto fail;
> 

FYI -
This particular commit didn't need to come back to any stable channels 
as the commit it fixed
b5006f873b99 ("drm/amd/display: initialize link_srv in virtual env")
is only present in 6.4.