Re: [PATCH] net: mac80211: rx.c: Use built-in RCU list checking
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2020-02-22 12:53:50
Also in:
linux-kernel-mentees, linux-wireless, lkml
Possibly related (same subject, not in this thread)
- 2020-02-22 · Re: [PATCH] net: mac80211: rx.c: Use built-in RCU list checking · Johannes Berg <johannes@sipsolutions.net>
- 2020-02-22 · [PATCH] net: mac80211: rx.c: Use built-in RCU list checking · <hidden>
On Sat, 2020-02-22 at 15:48 +0530, madhuparnabhowmik10@gmail.com wrote:
From: Madhuparna Bhowmik <redacted> list_for_each_entry_rcu() has built-in RCU and lock checking. Pass cond argument to list_for_each_entry_rcu() to silence false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled by default.
Umm. What warning?
quoted hunk
+++ b/net/mac80211/rx.c@@ -3547,7 +3547,8 @@ static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx, skb->pkt_type = PACKET_OTHERHOST; skb->protocol = htons(ETH_P_802_2); - list_for_each_entry_rcu(sdata, &local->interfaces, list) { + list_for_each_entry_rcu(sdata, &local->interfaces, list, + lockdep_is_held(&rx->local->rx_path_lock)) { if (!ieee80211_sdata_running(sdata)) continue;
This is not related at all.
quoted hunk
@@ -4114,7 +4115,8 @@ 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_rcu(sta, &local->sta_list, list, + lockdep_is_held(&local->sta_mtx)) {
And this isn't even a real RCU iteration, since we _must_ hold the mutex here. johannes