From: Johannes Berg ieee80211_join_mesh() acquires a channel context and then calls ieee80211_start_mesh(), which can fail. In that case, the chanctx isn't released then interface removal will attempt to unassign it after it's removed from the driver, hitting: wlan0: Failed check-sdata-in-driver check, flags: 0x0 WARNING: net/mac80211/driver-ops.c:366 at drv_unassign_vif_chanctx ieee80211_assign_link_chanctx __ieee80211_link_release_channel ieee80211_link_release_channel ieee80211_teardown_sdata unregister_netdevice_many_notify _cfg80211_unregister_wdev ieee80211_remove_interfaces ieee80211_unregister_hw mac80211_hwsim_del_radio hwsim_exit_net Correctly release the channel on start failures. Assisted-by: LLM Reported-by: syzbot+63a84ea9c0f57d6133fa@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=63a84ea9c0f57d6133fa Fixes: 2b5e19677592 ("mac80211: cache mesh beacon") Link: https://patch.msgid.link/20260904170057.8c86b0a8a44f.If6d6e31f93aca94e992ae17edc691407b146537c@changeid Signed-off-by: Johannes Berg --- net/mac80211/cfg.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 2d5a0abe35db..d3558f0c7550 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -3323,7 +3323,11 @@ static int ieee80211_join_mesh(struct wiphy *wiphy, struct net_device *dev, if (err) return err; - return ieee80211_start_mesh(sdata); + err = ieee80211_start_mesh(sdata); + if (err) + ieee80211_link_release_channel(&sdata->deflink); + + return err; } static int ieee80211_leave_mesh(struct wiphy *wiphy, struct net_device *dev) -- 2.55.0