[PATCH v2] drm/xe/xe_devcoredump: Check NULL before dereferencing

[Souza, Jose]

On Wed, 2024-03-20 at 10:52 +0530, Himal Prasad Ghimiray wrote:
> Dereference 'coredump' to access 'xe_devcoredump_snapshot' only if
> 'coredump' is not NULL,
> 
> v2
> - Fix commit messages.
> 
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_devcoredump.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
> index 0fcd30680323..83a1f3cd37cf 100644
> --- a/drivers/gpu/drm/xe/xe_devcoredump.c
> +++ b/drivers/gpu/drm/xe/xe_devcoredump.c
> @@ -74,17 +74,20 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
>  				   size_t count, void *data, size_t datalen)
>  {
>  	struct xe_devcoredump *coredump = data;
> +	if (!coredump)
> +		return -ENODATA;
> +
>  	struct xe_device *xe = coredump_to_xe(coredump);
> +	/* Our device is gone already... */
> +	if (!xe)
> +		return -ENODEV;
> +
>  	struct xe_devcoredump_snapshot *ss = &coredump->snapshot;
>  	struct drm_printer p;
>  	struct drm_print_iterator iter;
>  	struct timespec64 ts;
>  	int i;
>  
> -	/* Our device is gone already... */
> -	if (!data || !coredump_to_xe(coredump))
> -		return -ENODEV;

All variables must be defined before any code.

> -
>  	/* Ensure delayed work is captured before continuing */
>  	flush_work(&ss->work);
>