Re: [PATCH] remoteproc: imx_rproc: Not report loaded resource table when none

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Good day,

On Thu, Jan 22, 2026 at 11:24:43AM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> When starting a firmware without a resource table after previously running
> one that had a resource table, imx_rproc_elf_find_loaded_rsc_table() may
> incorrectly return a valid device memory pointer (priv->rsc_table).

priv->rsc_table is not NULL if the DT has a "rsc-table" entry, indicating that
_if_ there is a resource table in memory, that's where it should be.  Function
imx_rproc_elf_find_loaded_rsc_table() is buggy so the narrative about a
previously running FW with a valid resource table can be dropped.

> 
> In this case rproc->cached_table is NULL because the current firmware does
> not contain a resource table, but the remoteproc core still interprets the
> non-NULL return value as a loaded resource table and attempts to memcpy()
> from rproc->cached_table, leading to a NULL pointer dereference and kernel
> panic.
> 
> Fix this by returning NULL from imx_rproc_elf_find_loaded_rsc_table() when
> there is no cached resource table for the current firmware. This ensures
> that a loaded resource table is only reported when a valid cached_table
> exists, which matches the remoteproc core expectations.
> 
> This issue can be reproduced by:
>   1) start a firmware with a resource table
>   2) stop the remote processor
>   3) start a firmware without a resource table
> 
> With this change, starting a firmware without a resource table no longer
> causes kernel dump.
> 
> Fixes: e954a1bd1610 ("remoteproc: imx_rproc: Use imx specific hook for find_loaded_rsc_table")
> Cc: stable@vger.kernel.org
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/remoteproc/imx_rproc.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index 375de79168a1c8d11b87ac1bd63774a3feac106d..cf044b385b58fe1e17d0fc440c243d76ecf020ae 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -729,6 +729,10 @@ imx_rproc_elf_find_loaded_rsc_table(struct rproc *rproc, const struct firmware *
>  {
>  	struct imx_rproc *priv = rproc->priv;
>  
> +	/* No resource table in the firmware */
> +	if (!rproc->cached_table)
> +		return NULL;
> +

I think rproc->cached_table should be kept for internal remoteproc core usage
only.  Please use rproc->table_ptr.

Thanks,
Mathieu

>  	if (priv->rsc_table)
>  		return (struct resource_table *)priv->rsc_table;
>  
> 
> ---
> base-commit: e3b32dcb9f23e3c3927ef3eec6a5842a988fb574
> change-id: 20260122-imx-rproc-fix-e206f8e6e477
> 
> Best regards,
> -- 
> Peng Fan <peng.fan@nxp.com>
>