Patch "mac80211: flush hw_roc_start work before cancelling the ROC" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

mac80211: flush hw_roc_start work before cancelling the ROC

to the 4.9-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:
mac80211-flush-hw_roc_start-work-before-cancelling-the-roc.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Avraham Stern <[email protected]>
Date: Fri, 18 Aug 2017 15:33:57 +0300
Subject: mac80211: flush hw_roc_start work before cancelling the ROC

From: Avraham Stern <[email protected]>

commit 6e46d8ce894374fc135c96a8d1057c6af1fef237 upstream.

When HW ROC is supported it is possible that after the HW notified that the ROC has started, the ROC was cancelled and another ROC was added while the hw_roc_start worker is waiting on the mutex (since cancelling the ROC and adding another one also holds the same mutex). As a result, the hw_roc_start worker will continue to run after the new ROC is added but before it is actually started by the HW. This may result in notifying userspace that the ROC has started before it actually does, or in case of management tx ROC, in an attempt to tx while not on the right channel.

In addition, when the driver will notify mac80211 that the second ROC has started, mac80211 will warn that this ROC has already been notified.

Fix this by flushing the hw_roc_start work before cancelling an ROC.

---
 net/mac80211/offchannel.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -707,6 +707,8 @@ static int ieee80211_cancel_roc(struct i
 	if (!cookie)
 		return -ENOENT;
 
+	flush_work(&local->hw_roc_start);
+
 	mutex_lock(&local->mtx);
 	list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 		if (!mgmt_tx && roc->cookie != cookie)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mac80211-flush-hw_roc_start-work-before-cancelling-the-roc.patch