Patch "mac80211: flush hw_roc_start work before cancelling the ROC" has been added to the 4.4-stable tree

Patch "mac80211: flush hw_roc_start work before cancelling the ROC" has been added to the 4.4-stable tree

[gregkh]

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 4.4-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-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6e46d8ce894374fc135c96a8d1057c6af1fef237 Mon Sep 17 00:00:00 2001
From: Avraham Stern <avraham.stern@intel.com>
Date: Fri, 18 Aug 2017 15:33:57 +0300
Subject: mac80211: flush hw_roc_start work before cancelling the ROC

From: Avraham Stern <avraham.stern@intel.com>

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.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -469,6 +469,8 @@ void ieee80211_roc_purge(struct ieee8021
 	struct ieee80211_roc_work *roc, *tmp;
 	LIST_HEAD(tmp_list);
 
+	flush_work(&local->hw_roc_start);
+
 	mutex_lock(&local->mtx);
 	list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
 		if (sdata && roc->sdata != sdata)


Patches currently in stable-queue which might be from avraham.stern@intel.com are

queue-4.4/mac80211-flush-hw_roc_start-work-before-cancelling-the-roc.patch