[PATCH wireless] wifi: mac80211: skip BSS_CHANGED_TXPOWER for monitor interfaces

[Dhyan K Prajapati <dhyan19022009@gmail.com>]

Monitor mode interfaces do not maintain a BSS context, since a commit in
July 2025 monitor interfaces with WANT_MONITOR_VIF began receiving link
change notification duing ieee80211_add_vitual_monitor(), when
ieee_assign_link_chanctx() assigns a channel context, it triggers
ieee80211_recalc_txpower() this sends a bss_info_changed callback
receive link->conf as the bss_conf prameter, in monitor mode it isn't
initialised leading to NULL pointer dereference in drivers like iwldvm,
as BSS_CHANGED_TXPOWER is not applicable for monitor mode we can just
skip it.

Fixes: c57e5b9819df ("wifi: mac80211: fix WARN_ON for monitor mode on some devices")
Tested-by: Dhyan K Prajapati <dhyan1902209@gmail.com>
Signed-off-by: Dhyan K Prajapati <dhyan19022009@gmail.com>
---
 net/mac80211/iface.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 515384ca2..47f6bef0e 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -76,8 +76,9 @@ bool __ieee80211_recalc_txpower(struct ieee80211_link_data *link)
 void ieee80211_recalc_txpower(struct ieee80211_link_data *link,
 			      bool update_bss)
 {
-	if (__ieee80211_recalc_txpower(link) ||
-	    (update_bss && ieee80211_sdata_running(link->sdata)))
+	if (link->sdata->vif.type != NL80211_IFTYPE_MONITOR &&
+	    (__ieee80211_recalc_txpower(link) ||
+	     (update_bss && ieee80211_sdata_running(link->sdata))))
 		ieee80211_link_info_change_notify(link->sdata, link,
 						  BSS_CHANGED_TXPOWER);
 }
-- 
2.43.0