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

From: Kalle Valo <[email-masked]>
Date: Tue, 1 Sep 2020 09:34:04 +0000 (UTC)

Jia-Ju Bai <[email-masked]> 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: <[email-masked]>
> Signed-off-by: Jia-Ju Bai <[email-masked]>
> Acked-by: Christian Lamparter <[email-masked]>

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