From: Arnd Bergmann <[email protected]>
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 <[email protected]>
---
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
Arnd Bergmann <[email protected]> writes:
> From: Arnd Bergmann <[email protected]>
>
> 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 <[email protected]>
> ---
> 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
On 14/10/2021 04:51, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> 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 <[email protected]>
Reviewed-by: Fabio Estevam <[email protected]>
Arnd Bergmann <[email protected]> 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 <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>
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/[email protected]/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches