2024-01-13 04:22:48

by Nikita Yushchenko

[permalink] [raw]
Subject: [PATCH] net: ravb: Fix dma_addr_t truncation in error case

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 <[email protected]>
---
drivers/net/ethernet/renesas/ravb_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 8649b3e90edb..0e3731f50fc2 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1949,7 +1949,7 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
struct ravb_tstamp_skb *ts_skb;
struct ravb_tx_desc *desc;
unsigned long flags;
- u32 dma_addr;
+ dma_addr_t dma_addr;
void *buffer;
u32 entry;
u32 len;
--
2.39.2



2024-01-13 08:31:33

by Niklas Söderlund

[permalink] [raw]
Subject: Re: [PATCH] net: ravb: Fix dma_addr_t truncation in error case

Hello Nikita,

Thanks for your patch.

On 2024-01-13 10:22:21 +0600, 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 <[email protected]>

Reviewed-by: Niklas Söderlund <[email protected]>

> ---
> drivers/net/ethernet/renesas/ravb_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index 8649b3e90edb..0e3731f50fc2 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -1949,7 +1949,7 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
> struct ravb_tstamp_skb *ts_skb;
> struct ravb_tx_desc *desc;
> unsigned long flags;
> - u32 dma_addr;
> + dma_addr_t dma_addr;
> void *buffer;
> u32 entry;
> u32 len;
> --
> 2.39.2
>
>

--
Kind Regards,
Niklas Söderlund

2024-01-13 09:43:29

by Sergey Shtylyov

[permalink] [raw]
Subject: Re: [PATCH] net: ravb: Fix dma_addr_t truncation in error case

On 1/13/24 7:22 AM, 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 <[email protected]>

Reviewed-by: Sergey Shtylyov <[email protected]>

[...]

MBR, Sergey

2024-01-13 21:03:35

by Florian Fainelli

[permalink] [raw]
Subject: Re: [PATCH] net: ravb: Fix dma_addr_t truncation in error case



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 <[email protected]>

Reviewed-by: Florian Fainelli <[email protected]>

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

2024-01-14 16:50:35

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH] net: ravb: Fix dma_addr_t truncation in error case

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <[email protected]>:

On Sat, 13 Jan 2024 10:22:21 +0600 you 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.
>
> [...]

Here is the summary with links:
- net: ravb: Fix dma_addr_t truncation in error case
https://git.kernel.org/netdev/net/c/e327b2372bc0

You are awesome, thank you!
--
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