This is a note to let you know that I've just added the patch titled mt76: fix a possible NULL pointer dereference in mt76_testmode_dump to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mt76-fix-a-possible-null-pointer-dereference-in-mt76.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit fa6872117b9f6d769b1d7cd5c6abcafa58614f1d Author: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> Date: Fri Aug 21 12:52:15 2020 +0200 mt76: fix a possible NULL pointer dereference in mt76_testmode_dump [ Upstream commit ce8463a726a5669b200a1c2c17f95bc1394cc6bf ] Fix a possible NULL pointer dereference in mt76_testmode_dump() since nla_nest_start returns NULL in case of error Fixes: f0efa8621550e ("mt76: add API for testmode support") Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> Signed-off-by: Felix Fietkau <nbd@xxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/wireless/mediatek/mt76/testmode.c b/drivers/net/wireless/mediatek/mt76/testmode.c index 75bb02cdfdae4..5bd6ac1ba3b5b 100644 --- a/drivers/net/wireless/mediatek/mt76/testmode.c +++ b/drivers/net/wireless/mediatek/mt76/testmode.c @@ -442,9 +442,13 @@ int mt76_testmode_dump(struct ieee80211_hw *hw, struct sk_buff *msg, mutex_lock(&dev->mutex); if (tb[MT76_TM_ATTR_STATS]) { + err = -EINVAL; + a = nla_nest_start(msg, MT76_TM_ATTR_STATS); - err = mt76_testmode_dump_stats(dev, msg); - nla_nest_end(msg, a); + if (a) { + err = mt76_testmode_dump_stats(dev, msg); + nla_nest_end(msg, a); + } goto out; }