[PATCH 1/2] mt76: mt7915: fix unused 'mode' variable

From: Arnd Bergmann <arnd@arndb.de>

clang points out a possible corner case in the mt7915_tm_set_tx_cont()
function if called with invalid arguments:

drivers/net/wireless/mediatek/mt76/mt7915/testmode.c:593:2: warning: variable 'mode' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
        default:
        ^~~~~~~
drivers/net/wireless/mediatek/mt76/mt7915/testmode.c:597:13: note: uninitialized use occurs here
        rateval =  mode << 6 | rate_idx;
                   ^~~~
drivers/net/wireless/mediatek/mt76/mt7915/testmode.c:506:37: note: initialize the variable 'mode' to silence this warning
        u8 rate_idx = td->tx_rate_idx, mode;
                                           ^

Change it to return an error instead of continuing with invalid data
here.

Fixes: 3f0caa3cbf94 ("mt76: mt7915: add support for continuous tx in testmode")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/mediatek/mt76/mt7915/testmode.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/testmode.c b/drivers/net/wireless/mediatek/mt76/mt7915/testmode.c
index 7fb2170a9561..aa629e1fb420 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/testmode.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/testmode.c

@@ -543,6 +543,7 @@ mt7915_tm_set_tx_cont(struct mt7915_phy *phy, bool en)
 		tx_cont->bw = CMD_CBW_20MHZ;
 		break;
 	default:
+		return -EINVAL;
 		break;
 	}
 

@@ -591,6 +592,7 @@ mt7915_tm_set_tx_cont(struct mt7915_phy *phy, bool en)
 		mode = MT_PHY_TYPE_HE_MU;
 		break;
 	default:
+		return -EINVAL;
 		break;
 	}
 

-- 
2.29.2

From: Arnd Bergmann <arnd@arndb.de>

Clang points out a mistake in the error handling in
mt7921_mcu_tx_rate_report(), which tries to dereference a pointer that
cannot be initialized because of the error that is being handled:

drivers/net/wireless/mediatek/mt76/mt7921/mcu.c:409:3: warning: variable 'stats' is uninitialized when used here [-Wuninitialized]
                stats->tx_rate = rate;
                ^~~~~
drivers/net/wireless/mediatek/mt76/mt7921/mcu.c:401:32: note: initialize the variable 'stats' to silence this warning
        struct mt7921_sta_stats *stats;
                                      ^
Just remove the obviously incorrect line.

Fixes: 1c099ab44727 ("mt76: mt7921: add MCU support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/mediatek/mt76/mt7921/mcu.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
index db125cd22b91..b5cc72e7e81c 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c

@@ -405,10 +405,8 @@ mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb,
 	if (wlan_idx >= MT76_N_WCIDS)
 		return;
 	wcid = rcu_dereference(dev->mt76.wcid[wlan_idx]);
-	if (!wcid) {
-		stats->tx_rate = rate;
+	if (!wcid)
 		return;
-	}
 
 	msta = container_of(wcid, struct mt7921_sta, wcid);
 	stats = &msta->stats;

-- 
2.29.2

On Thu, Feb 25, 2021 at 7:00 AM Arnd Bergmann [off-list ref] wrote:

From: Arnd Bergmann <arnd@arndb.de>

Clang points out a mistake in the error handling in
mt7921_mcu_tx_rate_report(), which tries to dereference a pointer that
cannot be initialized because of the error that is being handled:

drivers/net/wireless/mediatek/mt76/mt7921/mcu.c:409:3: warning: variable 'stats' is uninitialized when used here [-Wuninitialized]
                stats->tx_rate = rate;
                ^~~~~
drivers/net/wireless/mediatek/mt76/mt7921/mcu.c:401:32: note: initialize the variable 'stats' to silence this warning
        struct mt7921_sta_stats *stats;
                                      ^
Just remove the obviously incorrect line.

Yeah, looks like perhaps a small mistake from when the driver was
introduced. Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

-- 
Thanks,
~Nick Desaulniers

Arnd Bergmann [off-list ref] wrote:

From: Arnd Bergmann <arnd@arndb.de>

Clang points out a mistake in the error handling in
mt7921_mcu_tx_rate_report(), which tries to dereference a pointer that
cannot be initialized because of the error that is being handled:

drivers/net/wireless/mediatek/mt76/mt7921/mcu.c:409:3: warning: variable 'stats' is uninitialized when used here [-Wuninitialized]
                stats->tx_rate = rate;
                ^~~~~
drivers/net/wireless/mediatek/mt76/mt7921/mcu.c:401:32: note: initialize the variable 'stats' to silence this warning
        struct mt7921_sta_stats *stats;
                                      ^
Just remove the obviously incorrect line.

Fixes: 1c099ab44727 ("mt76: mt7921: add MCU support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

Patch applied to wireless-drivers.git, thanks.

fb5fabb192b2 mt76: mt7921: remove incorrect error handling

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210225145953.404859-2-arnd@kernel.org/

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

On Thu, Feb 25, 2021 at 03:59:14PM +0100, Arnd Bergmann wrote:

Remove the break if we are adding a return?

Arnd Bergmann [off-list ref] wrote:

From: Arnd Bergmann <arnd@arndb.de>

clang points out a possible corner case in the mt7915_tm_set_tx_cont()
function if called with invalid arguments:

drivers/net/wireless/mediatek/mt76/mt7915/testmode.c:593:2: warning: variable 'mode' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
        default:
        ^~~~~~~
drivers/net/wireless/mediatek/mt76/mt7915/testmode.c:597:13: note: uninitialized use occurs here
        rateval =  mode << 6 | rate_idx;
                   ^~~~
drivers/net/wireless/mediatek/mt76/mt7915/testmode.c:506:37: note: initialize the variable 'mode' to silence this warning
        u8 rate_idx = td->tx_rate_idx, mode;
                                           ^

Change it to return an error instead of continuing with invalid data
here.

Fixes: 3f0caa3cbf94 ("mt76: mt7915: add support for continuous tx in testmode")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Please remove the break and send v2.

Patch set to Changes Requested.

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210225145953.404859-1-arnd@kernel.org/

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