Re: [PATCH V1] accel/amdxdna: Guard management mailbox channel cleanup against NULL pointer

[Mario Limonciello <superm1@kernel.org>]

On 4/16/26 15:11, Lizhi Hou wrote:
> From: Max Zhen <max.zhen@amd.com>
> 
> The management mailbox channel cleanup helpers can be called from
> error handling paths when mgmt_chann has already been destroyed.
> 
> Add NULL checks to xdna_mailbox_free_channel() and
> xdna_mailbox_stop_channel() so the cleanup path safely returns instead
> of dereferencing a NULL mailbox channel pointer.
> 
> Fixes: b87f920b9344 ("accel/amdxdna: Support hardware mailbox")
> Signed-off-by: Max Zhen <max.zhen@amd.com>
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
> ---
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
>   drivers/accel/amdxdna/amdxdna_mailbox.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/accel/amdxdna/amdxdna_mailbox.c b/drivers/accel/amdxdna/amdxdna_mailbox.c
> index 336e5e77f18a..37771bdb24a1 100644
> --- a/drivers/accel/amdxdna/amdxdna_mailbox.c
> +++ b/drivers/accel/amdxdna/amdxdna_mailbox.c
> @@ -496,6 +496,9 @@ struct mailbox_channel *xdna_mailbox_alloc_channel(struct mailbox *mb)
>   
>   void xdna_mailbox_free_channel(struct mailbox_channel *mb_chann)
>   {
> +	if (!mb_chann)
> +		return;
> +
>   	destroy_workqueue(mb_chann->work_q);
>   	kfree(mb_chann);
>   }
> @@ -542,6 +545,9 @@ void xdna_mailbox_stop_channel(struct mailbox_channel *mb_chann)
>   	struct mailbox_msg *mb_msg;
>   	unsigned long msg_id;
>   
> +	if (!mb_chann)
> +		return;
> +
>   	/* Disable an irq and wait. This might sleep. */
>   	free_irq(mb_chann->msix_irq, mb_chann);
>