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Date: Sat, 13 Jan 2024 13:03:14 -0800
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Subject: Re: [PATCH] net: ravb: Fix dma_addr_t truncation in error case
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To: Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
 "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>,
 Paolo Abeni <pabeni@redhat.com>
Cc: Sergey Shtylyov <s.shtylyov@omp.ru>,
 Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>,
 Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
 Wolfram Sang <wsa+renesas@sang-engineering.com>,
 =?UTF-8?Q?Uwe_Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>,
 netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
 linux-kernel@vger.kernel.org
References: <20240113042221.480650-1-nikita.yoush@cogentembedded.com>
From: Florian Fainelli <f.fainelli@gmail.com>
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In-Reply-To: <20240113042221.480650-1-nikita.yoush@cogentembedded.com>
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On 1/12/2024 8:22 PM, Nikita Yushchenko wrote:
> In ravb_start_xmit(), ravb driver uses u32 variable to store result of
> dma_map_single() call. Since ravb hardware has 32-bit address fields in
> descriptors, this works properly when mapping is successful - it is
> platform's job to provide mapping addresses that fit into hardware
> limitations.
> 
> However, in failure case dma_map_single() returns DMA_MAPPING_ERROR
> constant that is 64-bit when dma_addr_t is 64-bit. Storing this constant
> in u32 leads to truncation, and further call to dma_mapping_error()
> fails to notice the error.
> 
> Fix that by storing result of dma_map_single() in a dma_addr_t
> variable.
> 
> Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>

Nit: since this is a bug fix you should prefix your patches with "[PATCH 
net]", see:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/maintainer-netdev.rst#n62
-- 
Florian