mwifiex: add mutex lock for call in mwifiex_dfs_chan_sw_work_queue

stable inclusion
from stable-v5.10.121
commit 74ad0d7450206fb22a853c3c0a3a17d8734ecd2b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=74ad0d7450206fb22a853c3c0a3a17d8734ecd2b

--------------------------------

[ Upstream commit 3e12968f ]

cfg80211_ch_switch_notify uses ASSERT_WDEV_LOCK to assert that
net_device->ieee80211_ptr->mtx (which is the same as priv->wdev.mtx)
is held during the function's execution.
mwifiex_dfs_chan_sw_work_queue is one of its callers, which does not
hold that lock, therefore violating the assertion.
Add a lock around the call.

Disclaimer:
I am currently working on a static analyser to detect missing locks.
This was a reported case. I manually verified the report by looking
at the code, so that I do not send wrong information or patches.
After concluding that this seems to be a true positive, I created
this patch.
However, as I do not in fact have this particular hardware,
I was unable to test it.
Reviewed-by: NBrian Norris <briannorris@chromium.org>
Signed-off-by: NNiels Dossche <dossche.niels@gmail.com>
Signed-off-by: NKalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220321225515.32113-1-dossche.niels@gmail.comSigned-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/net/wireless/marvell/mwifiex/11h.c

@@ -303,5 +303,7 @@ void mwifiex_dfs_chan_sw_work_queue(struct work_struct *work)
 
 	mwifiex_dbg(priv->adapter, MSG,
 		    "indicating channel switch completion to kernel\n");
+	mutex_lock(&priv->wdev.mtx);
 	cfg80211_ch_switch_notify(priv->netdev, &priv->dfs_chandef);
+	mutex_unlock(&priv->wdev.mtx);
 }