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Subject: Re: [PATCH] ath10k: fix invalid dma_addr_t token assignment
From:   Kalle Valo <kvalo@codeaurora.org>
In-Reply-To: <20211014075153.3655910-1-arnd@kernel.org>
References: <20211014075153.3655910-1-arnd@kernel.org>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Alagu Sankar <alagusankar@silex-india.com>,
        Arnd Bergmann <arnd@arndb.de>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Brian Norris <briannorris@chromium.org>,
        Wen Gong <wgong@codeaurora.org>,
        Tamizh Chelvam <tamizhr@codeaurora.org>,
        Carl Huang <cjhuang@codeaurora.org>,
        Miaoqing Pan <miaoqing@codeaurora.org>,
        Ben Greear <greearb@candelatech.com>,
        Erik Stromdahl <erik.stromdahl@gmail.com>,
        Fabio Estevam <festevam@denx.de>, ath10k@lists.infradead.org,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Message-ID: <163516705229.3976.16508438608512725859.kvalo@codeaurora.org>
Date:   Mon, 25 Oct 2021 13:04:19 +0000 (UTC)
Precedence: bulk

Arnd Bergmann <arnd@kernel.org> wrote:

> Using a kernel pointer in place of a dma_addr_t token can
> lead to undefined behavior if that makes it into cache
> management functions. The compiler caught one such attempt
> in a cast:
> 
> drivers/net/wireless/ath/ath10k/mac.c: In function 'ath10k_add_interface':
> drivers/net/wireless/ath/ath10k/mac.c:5586:47: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
>  5586 |                         arvif->beacon_paddr = (dma_addr_t)arvif->beacon_buf;
>       |                                               ^
> 
> Looking through how this gets used down the way, I'm fairly
> sure that beacon_paddr is never accessed again for ATH10K_DEV_TYPE_HL
> devices, and if it was accessed, that would be a bug.
> 
> Change the assignment to use a known-invalid address token
> instead, which avoids the warning and makes it easier to catch
> bugs if it does end up getting used.
> 
> Fixes: e263bdab9c0e ("ath10k: high latency fixes for beacon buffer")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

Patch applied to ath-next branch of ath.git, thanks.

937e79c67740 ath10k: fix invalid dma_addr_t token assignment

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20211014075153.3655910-1-arnd@kernel.org/

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