Re: p54: avoid accessing the data mapped to streaming DMA

From: Kalle Valo
Date: Tue Sep 01 2020 - 05:34:22 EST


Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx> wrote:

> In p54p_tx(), skb->data is mapped to streaming DMA on line 337:
> mapping = pci_map_single(..., skb->data, ...);
>
> Then skb->data is accessed on line 349:
> desc->device_addr = ((struct p54_hdr *)skb->data)->req_id;
>
> This access may cause data inconsistency between CPU cache and hardware.
>
> To fix this problem, ((struct p54_hdr *)skb->data)->req_id is stored in
> a local variable before DMA mapping, and then the driver accesses this
> local variable instead of skb->data.
>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx>
> Acked-by: Christian Lamparter <chunkeey@xxxxxxxxx>

Patch applied to wireless-drivers-next.git, thanks.

478762855b5a p54: avoid accessing the data mapped to streaming DMA

--
https://patchwork.kernel.org/patch/11696391/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches