From: Chad Monroe Date: Mon, 8 Dec 2025 14:31:32 +0000 (+0000) Subject: wifi: mt76: fix deadlock in remain-on-channel X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6939b97ddad3cf3dfbb3b5a0a12ef79cb886747e;p=thirdparty%2Flinux.git wifi: mt76: fix deadlock in remain-on-channel mt76_remain_on_channel() and mt76_roc_complete() call mt76_set_channel() while already holding dev->mutex. Since mt76_set_channel() also acquires dev->mutex, this results in a deadlock. Use __mt76_set_channel() instead of mt76_set_channel(). Add cancel_delayed_work_sync() for mac_work before acquiring the mutex in mt76_remain_on_channel() to prevent a secondary deadlock with the mac_work workqueue. Fixes: a8f424c1287c ("wifi: mt76: add multi-radio remain_on_channel functions") Signed-off-by: Chad Monroe Link: https://patch.msgid.link/ace737e7b621af7c2adb33b0188011a5c1de2166.1765204256.git.chad@monroe.io Signed-off-by: Felix Fietkau --- diff --git a/drivers/net/wireless/mediatek/mt76/channel.c b/drivers/net/wireless/mediatek/mt76/channel.c index 2b705bdb7993c..d9f8529db7ed4 100644 --- a/drivers/net/wireless/mediatek/mt76/channel.c +++ b/drivers/net/wireless/mediatek/mt76/channel.c @@ -326,7 +326,7 @@ void mt76_roc_complete(struct mt76_phy *phy) mlink->mvif->roc_phy = NULL; if (phy->main_chandef.chan && !test_bit(MT76_MCU_RESET, &dev->phy.state)) - mt76_set_channel(phy, &phy->main_chandef, false); + __mt76_set_channel(phy, &phy->main_chandef, false); mt76_put_vif_phy_link(phy, phy->roc_vif, phy->roc_link); phy->roc_vif = NULL; phy->roc_link = NULL; @@ -370,6 +370,8 @@ int mt76_remain_on_channel(struct ieee80211_hw *hw, struct ieee80211_vif *vif, if (!phy) return -EINVAL; + cancel_delayed_work_sync(&phy->mac_work); + mutex_lock(&dev->mutex); if (phy->roc_vif || dev->scan.phy == phy || @@ -388,7 +390,14 @@ int mt76_remain_on_channel(struct ieee80211_hw *hw, struct ieee80211_vif *vif, phy->roc_vif = vif; phy->roc_link = mlink; cfg80211_chandef_create(&chandef, chan, NL80211_CHAN_HT20); - mt76_set_channel(phy, &chandef, true); + ret = __mt76_set_channel(phy, &chandef, true); + if (ret) { + mlink->mvif->roc_phy = NULL; + phy->roc_vif = NULL; + phy->roc_link = NULL; + mt76_put_vif_phy_link(phy, vif, mlink); + goto out; + } ieee80211_ready_on_channel(hw); ieee80211_queue_delayed_work(phy->hw, &phy->roc_work, msecs_to_jiffies(duration));