2021-12-02 08:52:41

by Loic Poulain

Subject: [PATCH] wcn36xx: Fix max channels retrieval

Kernel test robot reported:drivers/net/wireless/ath/wcn36xx/smd.c:943:33:
sparse: sparse: cast truncates bits from constant value (780 becomes 80)

The 'channels' field is not a simple u8 array but an array of
channel_params. Using sizeof for retrieving the max number of
channels is then wrong.

In practice, it was not an issue, because the sizeof returned
value is 780, which is truncated in min_t (u8) to 80, which is
the value we expect...

Fix that properly using ARRAY_SIZE instead of sizeof.

Fixes: d707f812bb05 ("wcn36xx: Channel list update before hardware scan")
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Loic Poulain <[email protected]>
---
drivers/net/wireless/ath/wcn36xx/smd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/wcn36xx/smd.c b/drivers/net/wireless/ath/wcn36xx/smd.c
index ed45e2cf..900e5a5 100644
--- a/drivers/net/wireless/ath/wcn36xx/smd.c
+++ b/drivers/net/wireless/ath/wcn36xx/smd.c
@@ -940,7 +940,7 @@ int wcn36xx_smd_update_channel_list(struct wcn36xx *wcn, struct cfg80211_scan_re

INIT_HAL_MSG((*msg_body), WCN36XX_HAL_UPDATE_CHANNEL_LIST_REQ);

- msg_body->num_channel = min_t(u8, req->n_channels, sizeof(msg_body->channels));
+ msg_body->num_channel = min_t(u8, req->n_channels, ARRAY_SIZE(msg_body->channels));
for (i = 0; i < msg_body->num_channel; i++) {
struct wcn36xx_hal_channel_param *param = &msg_body->channels[i];
u32 min_power = WCN36XX_HAL_DEFAULT_MIN_POWER;
--
2.7.4

2021-12-08 08:34:46

by Kalle Valo

Subject: Re: [PATCH] wcn36xx: Fix max channels retrieval

Loic Poulain <[email protected]> wrote:

> Kernel test robot reported:drivers/net/wireless/ath/wcn36xx/smd.c:943:33:
> sparse: sparse: cast truncates bits from constant value (780 becomes 80)
>
> The 'channels' field is not a simple u8 array but an array of
> channel_params. Using sizeof for retrieving the max number of
> channels is then wrong.
>
> In practice, it was not an issue, because the sizeof returned
> value is 780, which is truncated in min_t (u8) to 80, which is
> the value we expect...
>
> Fix that properly using ARRAY_SIZE instead of sizeof.
>
> Fixes: d707f812bb05 ("wcn36xx: Channel list update before hardware scan")
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Loic Poulain <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>

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

09cab4308bf9 wcn36xx: Fix max channels retrieval

--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/

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