[PATCH 5.17 087/219] cfg80211: hold bss_lock while updating nontrans_list

Greg Kroah-Hartman
2022-04-18T12:24:50Z

From: Rameshkumar Sundaram <quic_ramess@quicinc.com>

[ Upstream commit a5199b5626cd6913cf8776a835bc63d40e0686ad ]

Synchronize additions to nontrans_list of transmitting BSS with
bss_lock to avoid races. Also when cfg80211_add_nontrans_list() fails
__cfg80211_unlink_bss() needs bss_lock to be held (has lockdep assert
on bss_lock). So protect the whole block with bss_lock to avoid
races and warnings. Found during code review.

Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning")
Signed-off-by: Rameshkumar Sundaram <quic_ramess@quicinc.com>
Link: https://lore.kernel.org/r/1649668071-9370-1-git-send-email-quic_ramess@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/wireless/scan.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index b2fdac96bab0..4a6d86432910 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -2018,11 +2018,13 @@ cfg80211_inform_single_bss_data(struct wiphy *wiphy,
/* this is a nontransmitting bss, we need to add it to
* transmitting bss' list if it is not there
*/
+ spin_lock_bh(&rdev->bss_lock);
if (cfg80211_add_nontrans_list(non_tx_data->tx_bss,
&res->pub)) {
if (__cfg80211_unlink_bss(rdev, res))
rdev->bss_generation++;
}
+ spin_unlock_bh(&rdev->bss_lock);
}

trace_cfg80211_return_bss(&res->pub);
--
2.35.1