Hi Johannes,
Am 22.07.25 um 14:11 schrieb Johannes Berg:
On Thu, 2025-07-10 at 09:47 +0200, Martin Kaistra wrote:
Hi,
when trying to use monitor mode with either rtl8xxxu or rtlwifi driver I get a
"Failed check-sdata-in-driver check" warning in
ieee80211_link_info_change_notify(). Aside from the warning, monitor mode seems
to work fine. This might also affect other drivers, I just don't have the
hardware to test.
I bisected and found that the warning started with c4382d5ca1af ("wifi:
mac80211: update the right link for tx power").
I can make the warning go away when I add WANT_MONITOR_VIF to the driver, but
the real fix should probably go in mac80211.
Strange, I'm not sure I see the relation with the commit you mention.
Before the mentioned commit __ieee80211_recalc_txpower() returns false and so
ieee80211_link_info_change_notify() doesn't get called.
Either way though, given NO_VIRTUAL_MONITOR and WANT_MONITOR_VIF we
probably have to catch it in the code, perhaps like the below? But I'm
not sure it handles NO_VIRTUAL_MONITOR correctly? Hm.
I can confirm that with the code snippet (with an added curly brace) I don't get
the warning anymore.
martin
johannes
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 351564360c26..bf338024b5d5 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -408,9 +408,20 @@ void ieee80211_link_info_change_notify(struct ieee80211_sub_if_data *sdata,
WARN_ON_ONCE(changed & BSS_CHANGED_VIF_CFG_FLAGS);
- if (!changed || sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+ if (!changed)
return;
+ switch (sdata->vif.type)
+ case NL80211_IFTYPE_AP_VLAN:
+ return;
+ case NL80211_IFTYPE_MONITOR:
+ if (!ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF))
+ return;
+ break;
+ default:
+ break;
+ }
+
if (!check_sdata_in_driver(sdata))
return;
