From: Johannes Berg <johannes.berg@xxxxxxxxx>
When we destroy the interface we already hold the wdev->mtx
while calling cfg80211_pmsr_wdev_down(), which assumes this
isn't true and flushes the worker that takes the lock, thus
leading to a deadlock.
Fix this by refactoring the worker and calling its code in
cfg80211_pmsr_wdev_down() directly.
We still need to flush the work later to make sure it's not
still running and will crash, but it will not do anything.
Fixes: 9bb7e0f24e7e ("cfg80211: add peer measurement with FTM initiator API")
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
net/wireless/core.c | 2 ++
net/wireless/pmsr.c | 22 +++++++++++++++-------
2 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 623dfe5e211c..b36ad8efb5e5 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -1068,6 +1068,8 @@ static void __cfg80211_unregister_wdev(struct wireless_dev *wdev, bool sync)
ASSERT_RTNL();
+ flush_work(&wdev->pmsr_free_wk);
+
nl80211_notify_iface(rdev, wdev, NL80211_CMD_DEL_INTERFACE);
list_del_rcu(&wdev->list);
diff --git a/net/wireless/pmsr.c b/net/wireless/pmsr.c
index f2e388e329fd..78c3f5633692 100644
--- a/net/wireless/pmsr.c
+++ b/net/wireless/pmsr.c
@@ -529,14 +529,14 @@ void cfg80211_pmsr_report(struct wireless_dev *wdev,
}
EXPORT_SYMBOL_GPL(cfg80211_pmsr_report);
-void cfg80211_pmsr_free_wk(struct work_struct *work)
+static void cfg80211_pmsr_process_abort(struct wireless_dev *wdev)
{
- struct wireless_dev *wdev = container_of(work, struct wireless_dev,
- pmsr_free_wk);
struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
struct cfg80211_pmsr_request *req, *tmp;
LIST_HEAD(free_list);
+ lockdep_assert_held(&wdev->mtx);
+
spin_lock_bh(&wdev->pmsr_lock);
list_for_each_entry_safe(req, tmp, &wdev->pmsr_list, list) {
if (req->nl_portid)
@@ -546,14 +546,22 @@ void cfg80211_pmsr_free_wk(struct work_struct *work)
spin_unlock_bh(&wdev->pmsr_lock);
list_for_each_entry_safe(req, tmp, &free_list, list) {
- wdev_lock(wdev);
rdev_abort_pmsr(rdev, wdev, req);
- wdev_unlock(wdev);
kfree(req);
}
}
+void cfg80211_pmsr_free_wk(struct work_struct *work)
+{
+ struct wireless_dev *wdev = container_of(work, struct wireless_dev,
+ pmsr_free_wk);
+
+ wdev_lock(wdev);
+ cfg80211_pmsr_process_abort(wdev);
+ wdev_unlock(wdev);
+}
+
void cfg80211_pmsr_wdev_down(struct wireless_dev *wdev)
{
struct cfg80211_pmsr_request *req;
@@ -567,8 +575,8 @@ void cfg80211_pmsr_wdev_down(struct wireless_dev *wdev)
spin_unlock_bh(&wdev->pmsr_lock);
if (found)
- schedule_work(&wdev->pmsr_free_wk);
- flush_work(&wdev->pmsr_free_wk);
+ cfg80211_pmsr_process_abort(wdev);
+
WARN_ON(!list_empty(&wdev->pmsr_list));
}
--
2.20.1
