* [PATCH] ath10k: fix invalid dma_addr_t token assignment
@ 2021-10-14 7:51 Arnd Bergmann
2021-10-18 13:10 ` Kalle Valo
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Arnd Bergmann @ 2021-10-14 7:51 UTC (permalink / raw)
To: Kalle Valo, Alagu Sankar
Cc: Arnd Bergmann, David S. Miller, Jakub Kicinski, Brian Norris,
Wen Gong, Tamizh Chelvam, Carl Huang, Miaoqing Pan, Ben Greear,
Erik Stromdahl, Fabio Estevam, ath10k, linux-wireless, netdev,
linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
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>
---
drivers/net/wireless/ath/ath10k/mac.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 7ca68c81d9b6..c0e78eaa65f8 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -5583,7 +5583,7 @@ static int ath10k_add_interface(struct ieee80211_hw *hw,
if (ar->bus_param.dev_type == ATH10K_DEV_TYPE_HL) {
arvif->beacon_buf = kmalloc(IEEE80211_MAX_FRAME_LEN,
GFP_KERNEL);
- arvif->beacon_paddr = (dma_addr_t)arvif->beacon_buf;
+ arvif->beacon_paddr = DMA_MAPPING_ERROR;
} else {
arvif->beacon_buf =
dma_alloc_coherent(ar->dev,
--
2.29.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] ath10k: fix invalid dma_addr_t token assignment
2021-10-14 7:51 [PATCH] ath10k: fix invalid dma_addr_t token assignment Arnd Bergmann
@ 2021-10-18 13:10 ` Kalle Valo
2021-10-25 12:16 ` Fabio Estevam
2021-10-25 13:04 ` Kalle Valo
2 siblings, 0 replies; 4+ messages in thread
From: Kalle Valo @ 2021-10-18 13:10 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Alagu Sankar, Arnd Bergmann, David S. Miller, Jakub Kicinski,
Brian Norris, Wen Gong, Tamizh Chelvam, Carl Huang, Miaoqing Pan,
Ben Greear, Erik Stromdahl, Fabio Estevam, ath10k,
linux-wireless, netdev, linux-kernel
Arnd Bergmann <arnd@kernel.org> writes:
> From: Arnd Bergmann <arnd@arndb.de>
>
> 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.
That's my understanding as well. beacon_paddr is only accessed in
ath10k_wmi_event_host_swba() and only low latency (ATH10K_DEV_TYPE_LL)
should use that function.
> 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>
> ---
> drivers/net/wireless/ath/ath10k/mac.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
> index 7ca68c81d9b6..c0e78eaa65f8 100644
> --- a/drivers/net/wireless/ath/ath10k/mac.c
> +++ b/drivers/net/wireless/ath/ath10k/mac.c
> @@ -5583,7 +5583,7 @@ static int ath10k_add_interface(struct ieee80211_hw *hw,
> if (ar->bus_param.dev_type == ATH10K_DEV_TYPE_HL) {
> arvif->beacon_buf = kmalloc(IEEE80211_MAX_FRAME_LEN,
> GFP_KERNEL);
> - arvif->beacon_paddr = (dma_addr_t)arvif->beacon_buf;
> + arvif->beacon_paddr = DMA_MAPPING_ERROR;
In the pending branch I added a comment here:
https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git/commit/?h=pending&id=02a383c9bf959147a95c4efeaa4edf35c4450fac
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] ath10k: fix invalid dma_addr_t token assignment
2021-10-14 7:51 [PATCH] ath10k: fix invalid dma_addr_t token assignment Arnd Bergmann
2021-10-18 13:10 ` Kalle Valo
@ 2021-10-25 12:16 ` Fabio Estevam
2021-10-25 13:04 ` Kalle Valo
2 siblings, 0 replies; 4+ messages in thread
From: Fabio Estevam @ 2021-10-25 12:16 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Kalle Valo, Alagu Sankar, Arnd Bergmann, David S. Miller,
Jakub Kicinski, Brian Norris, Wen Gong, Tamizh Chelvam,
Carl Huang, Miaoqing Pan, Ben Greear, Erik Stromdahl, ath10k,
linux-wireless, netdev, linux-kernel
On 14/10/2021 04:51, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> 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>
Reviewed-by: Fabio Estevam <festevam@denx.de>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] ath10k: fix invalid dma_addr_t token assignment
2021-10-14 7:51 [PATCH] ath10k: fix invalid dma_addr_t token assignment Arnd Bergmann
2021-10-18 13:10 ` Kalle Valo
2021-10-25 12:16 ` Fabio Estevam
@ 2021-10-25 13:04 ` Kalle Valo
2 siblings, 0 replies; 4+ messages in thread
From: Kalle Valo @ 2021-10-25 13:04 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Alagu Sankar, Arnd Bergmann, David S. Miller, Jakub Kicinski,
Brian Norris, Wen Gong, Tamizh Chelvam, Carl Huang, Miaoqing Pan,
Ben Greear, Erik Stromdahl, Fabio Estevam, ath10k,
linux-wireless, netdev, linux-kernel
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
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-10-14 7:51 [PATCH] ath10k: fix invalid dma_addr_t token assignment Arnd Bergmann
2021-10-18 13:10 ` Kalle Valo
2021-10-25 12:16 ` Fabio Estevam
2021-10-25 13:04 ` Kalle Valo
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