[PATCH 4.9 84/90] mac80211: rx: avoid RCU list traversal under mutex

From: Greg Kroah-Hartman
Date: Thu Mar 19 2020 - 09:14:17 EST


From: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>

[ Upstream commit 253216ffb2a002a682c6f68bd3adff5b98b71de8 ]

local->sta_mtx is held in __ieee80211_check_fast_rx_iface().
No need to use list_for_each_entry_rcu() as it also requires
a cond argument to avoid false lockdep warnings when not used in
RCU read-side section (with CONFIG_PROVE_RCU_LIST).
Therefore use list_for_each_entry();

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>
Link: https://lore.kernel.org/r/20200223143302.15390-1-madhuparnabhowmik10@xxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/mac80211/rx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 74652eb2f90fd..a6f265262f151 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3841,7 +3841,7 @@ void __ieee80211_check_fast_rx_iface(struct ieee80211_sub_if_data *sdata)

lockdep_assert_held(&local->sta_mtx);

- list_for_each_entry_rcu(sta, &local->sta_list, list) {
+ list_for_each_entry(sta, &local->sta_list, list) {
if (sdata != sta->sdata &&
(!sta->sdata->bss || sta->sdata->bss != sdata->bss))
continue;
--
2.20.1