From: Ilan Peer <[email protected]>
[ Upstream commit 45daaa1318410794de956fb8e9d06aed2dbb23d0 ]
The following race was possible:
1. The device driver requests HW restart.
2. A scan is requested from user space and is propagated
to the driver. During this flow HW_SCANNING flag is set.
3. The thread that handles the HW restart is scheduled,
and before starting the actual reconfiguration it
checks that HW_SCANNING is not set. The flow does so
without acquiring any lock, and thus the WARN fires.
Fix this by checking that HW_SCANNING is on only after RTNL is
acquired, i.e., user space scan request handling is no longer
in transit.
Signed-off-by: Ilan Peer <[email protected]>
Signed-off-by: Luca Coelho <[email protected]>
Link: https://lore.kernel.org/r/iwlwifi.20210618133832.8238ab3e19ab.I2693c581c70251472b4f9089e37e06fb2c18268f@changeid
Signed-off-by: Johannes Berg <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
net/mac80211/main.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 9dd741b68f26..937a024a13e2 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -257,14 +257,13 @@ static void ieee80211_restart_work(struct work_struct *work)
/* wait for scan work complete */
flush_workqueue(local->workqueue);
flush_work(&local->sched_scan_stopped_work);
+ flush_work(&local->radar_detected_work);
+
+ rtnl_lock();
WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),
"%s called with hardware scan in progress\n", __func__);
- flush_work(&local->radar_detected_work);
- /* we might do interface manipulations, so need both */
- rtnl_lock();
- wiphy_lock(local->hw.wiphy);
list_for_each_entry(sdata, &local->interfaces, list) {
/*
* XXX: there may be more work for other vif types and even
--
2.30.2