From: Yibo Zhao yiboz@codeaurora.org
[ Upstream commit 563572340173865a9a356e6bb02579e6998a876d ]
In multiple SSID cases, it takes time to prepare every AP interface to be ready in initializing phase. If a sta already knows everything it needs to join one of the APs and sends authentication to the AP which is not fully prepared at this point of time, AP's channel context could be NULL. As a result, warning message occurs.
Even worse, if the AP is under attack via tools such as MDK3 and massive authentication requests are received in a very short time, console will be hung due to kernel warning messages.
WARN_ON_ONCE() could be a better way for indicating warning messages without duplicate messages to flood the console.
Johannes: We still need to address the underlying problem, but we don't really have a good handle on it yet. Suppress the worst side-effects for now.
Signed-off-by: Zhi Chen zhichen@codeaurora.org Signed-off-by: Yibo Zhao yiboz@codeaurora.org [johannes: add note, change subject] Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/mac80211/ieee80211_i.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index e170f986d226..2878ea8a01fd 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1434,7 +1434,7 @@ ieee80211_get_sband(struct ieee80211_sub_if_data *sdata) rcu_read_lock(); chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
- if (WARN_ON(!chanctx_conf)) { + if (WARN_ON_ONCE(!chanctx_conf)) { rcu_read_unlock(); return NULL; }