[PATCH] wifi: mt76: mt7925: comprehensive stability fixes
Zac Bowling
zbowling at gmail.com
Fri Jan 2 12:05:24 PST 2026
From: Zac Bowling <zac at zacbowling.com>
This unified patch combines all MT7925 driver fixes for kernel stability:
1. NULL pointer dereference fixes in vif iteration, TX path, and MCU functions
2. Missing mutex protection in reset, ROC, PM, and resume paths
3. Error handling for MCU commands (AMPDU, BSS info, key setup)
4. lockdep assertions for debugging
5. MLO (Multi-Link Operation) improvements for roaming and AP mode
6. Firmware reload recovery after crashes
These fixes address kernel panics and system hangs that occur during:
- WiFi network switching and BSSID roaming
- Suspend/resume cycles
- MLO link state transitions
- Firmware recovery after crashes
Tested on Framework Desktop (AMD Ryzen AI Max 300) with MT7925 (RZ717).
Individual patches and detailed analysis available at:
https://github.com/zbowling/mt7925
Signed-off-by: Zac Bowling <zac at zacbowling.com>
---
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/init.c b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
index d7d5afe365ed..f800112ccaf7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
@@ -162,10 +162,17 @@ void mt7925_regd_update(struct mt792x_dev *dev)
if (!dev->regd_change)
return;
- mt7925_mcu_set_clc(dev, mdev->alpha2, dev->country_ie_env);
+ if (mt7925_mcu_set_clc(dev, mdev->alpha2, dev->country_ie_env) < 0)
+ dev_warn(dev->mt76.dev, "Failed to set CLC\n");
+
mt7925_regd_channel_update(wiphy, dev);
- mt7925_mcu_set_channel_domain(hw->priv);
- mt7925_set_tx_sar_pwr(hw, NULL);
+
+ if (mt7925_mcu_set_channel_domain(hw->priv) < 0)
+ dev_warn(dev->mt76.dev, "Failed to set channel domain\n");
+
+ if (mt7925_set_tx_sar_pwr(hw, NULL) < 0)
+ dev_warn(dev->mt76.dev, "Failed to set TX SAR power\n");
+
dev->regd_change = false;
}
EXPORT_SYMBOL_GPL(mt7925_regd_update);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
index 1e44e96f034e..a4109dc72163 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
@@ -1270,6 +1270,12 @@ mt7925_vif_connect_iter(void *priv, u8 *mac,
bss_conf = mt792x_vif_to_bss_conf(vif, i);
mconf = mt792x_vif_to_link(mvif, i);
+ /* Skip links that don't have bss_conf set up yet in mac80211.
+ * This can happen during HW reset when link state is inconsistent.
+ */
+ if (!bss_conf)
+ continue;
+
mt76_connac_mcu_uni_add_dev(&dev->mphy, bss_conf, &mconf->mt76,
&mvif->sta.deflink.wcid, true);
mt7925_mcu_set_tx(dev, bss_conf);
@@ -1324,9 +1330,11 @@ void mt7925_mac_reset_work(struct work_struct *work)
dev->hw_full_reset = false;
pm->suspended = false;
ieee80211_wake_queues(hw);
+ mt792x_mutex_acquire(dev);
ieee80211_iterate_active_interfaces(hw,
IEEE80211_IFACE_ITER_RESUME_ALL,
mt7925_vif_connect_iter, NULL);
+ mt792x_mutex_release(dev);
mt76_connac_power_save_sched(&dev->mt76.phy, pm);
mt792x_mutex_acquire(dev);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
index ac3d485a2f78..b6e3002faf41 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
@@ -596,6 +596,17 @@ static int mt7925_set_link_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
link_sta = sta ? mt792x_sta_to_link_sta(vif, sta, link_id) : NULL;
mconf = mt792x_vif_to_link(mvif, link_id);
mlink = mt792x_sta_to_link(msta, link_id);
+
+ if (!link_conf || !mconf || !mlink) {
+ /* During MLO roaming, link state may be torn down before
+ * mac80211 requests key removal. If removing a key and
+ * the link is already gone, consider it successfully removed.
+ */
+ if (cmd != SET_KEY)
+ return 0;
+ return -EINVAL;
+ }
+
wcid = &mlink->wcid;
wcid_keyidx = &wcid->hw_key_idx;
@@ -625,8 +636,10 @@ static int mt7925_set_link_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
struct mt792x_phy *phy = mt792x_hw_phy(hw);
mconf->mt76.cipher = mt7925_mcu_get_cipher(key->cipher);
- mt7925_mcu_add_bss_info(phy, mconf->mt76.ctx, link_conf,
- link_sta, true);
+ err = mt7925_mcu_add_bss_info(phy, mconf->mt76.ctx, link_conf,
+ link_sta, true);
+ if (err)
+ goto out;
}
if (cmd == SET_KEY)
@@ -743,9 +756,11 @@ void mt7925_set_runtime_pm(struct mt792x_dev *dev)
bool monitor = !!(hw->conf.flags & IEEE80211_CONF_MONITOR);
pm->enable = pm->enable_user && !monitor;
+ mt792x_mutex_acquire(dev);
ieee80211_iterate_active_interfaces(hw,
IEEE80211_IFACE_ITER_RESUME_ALL,
mt7925_pm_interface_iter, dev);
+ mt792x_mutex_release(dev);
pm->ds_enable = pm->ds_enable_user && !monitor;
mt7925_mcu_set_deep_sleep(dev, pm->ds_enable);
}
@@ -848,12 +863,17 @@ static int mt7925_mac_link_sta_add(struct mt76_dev *mdev,
msta = (struct mt792x_sta *)link_sta->sta->drv_priv;
mlink = mt792x_sta_to_link(msta, link_id);
+ if (!mlink)
+ return -EINVAL;
idx = mt76_wcid_alloc(dev->mt76.wcid_mask, MT792x_WTBL_STA - 1);
if (idx < 0)
return -ENOSPC;
mconf = mt792x_vif_to_link(mvif, link_id);
+ if (!mconf)
+ return -EINVAL;
+
mt76_wcid_init(&mlink->wcid, 0);
mlink->wcid.sta = 1;
mlink->wcid.idx = idx;
@@ -879,15 +899,20 @@ static int mt7925_mac_link_sta_add(struct mt76_dev *mdev,
MT_WTBL_UPDATE_ADM_COUNT_CLEAR);
link_conf = mt792x_vif_to_bss_conf(vif, link_id);
+ if (!link_conf)
+ return -EINVAL;
/* should update bss info before STA add */
if (vif->type == NL80211_IFTYPE_STATION && !link_sta->sta->tdls) {
if (ieee80211_vif_is_mld(vif))
- mt7925_mcu_add_bss_info(&dev->phy, mconf->mt76.ctx,
- link_conf, link_sta, link_sta != mlink->pri_link);
+ ret = mt7925_mcu_add_bss_info(&dev->phy, mconf->mt76.ctx,
+ link_conf, link_sta,
+ link_sta != mlink->pri_link);
else
- mt7925_mcu_add_bss_info(&dev->phy, mconf->mt76.ctx,
- link_conf, link_sta, false);
+ ret = mt7925_mcu_add_bss_info(&dev->phy, mconf->mt76.ctx,
+ link_conf, link_sta, false);
+ if (ret)
+ return ret;
}
if (ieee80211_vif_is_mld(vif) &&
@@ -985,18 +1010,29 @@ mt7925_mac_set_links(struct mt76_dev *mdev, struct ieee80211_vif *vif)
{
struct mt792x_dev *dev = container_of(mdev, struct mt792x_dev, mt76);
struct mt792x_vif *mvif = (struct mt792x_vif *)vif->drv_priv;
- struct ieee80211_bss_conf *link_conf =
- mt792x_vif_to_bss_conf(vif, mvif->deflink_id);
- struct cfg80211_chan_def *chandef = &link_conf->chanreq.oper;
- enum nl80211_band band = chandef->chan->band, secondary_band;
+ struct ieee80211_bss_conf *link_conf;
+ struct cfg80211_chan_def *chandef;
+ enum nl80211_band band, secondary_band;
+ u16 sel_links;
+ u8 secondary_link_id;
+
+ link_conf = mt792x_vif_to_bss_conf(vif, mvif->deflink_id);
+ if (!link_conf)
+ return;
+
+ chandef = &link_conf->chanreq.oper;
+ band = chandef->chan->band;
- u16 sel_links = mt76_select_links(vif, 2);
- u8 secondary_link_id = __ffs(~BIT(mvif->deflink_id) & sel_links);
+ sel_links = mt76_select_links(vif, 2);
+ secondary_link_id = __ffs(~BIT(mvif->deflink_id) & sel_links);
if (!ieee80211_vif_is_mld(vif) || hweight16(sel_links) < 2)
return;
link_conf = mt792x_vif_to_bss_conf(vif, secondary_link_id);
+ if (!link_conf)
+ return;
+
secondary_band = link_conf->chanreq.oper.chan->band;
if (band == NL80211_BAND_2GHZ ||
@@ -1024,6 +1060,8 @@ static void mt7925_mac_link_sta_assoc(struct mt76_dev *mdev,
msta = (struct mt792x_sta *)link_sta->sta->drv_priv;
mlink = mt792x_sta_to_link(msta, link_sta->link_id);
+ if (!mlink)
+ return;
mt792x_mutex_acquire(dev);
@@ -1033,12 +1071,13 @@ static void mt7925_mac_link_sta_assoc(struct mt76_dev *mdev,
link_conf = mt792x_vif_to_bss_conf(vif, vif->bss_conf.link_id);
}
- if (vif->type == NL80211_IFTYPE_STATION && !link_sta->sta->tdls) {
+ if (link_conf && vif->type == NL80211_IFTYPE_STATION && !link_sta->sta->tdls) {
struct mt792x_bss_conf *mconf;
mconf = mt792x_link_conf_to_mconf(link_conf);
- mt7925_mcu_add_bss_info(&dev->phy, mconf->mt76.ctx,
- link_conf, link_sta, true);
+ if (mconf)
+ mt7925_mcu_add_bss_info(&dev->phy, mconf->mt76.ctx,
+ link_conf, link_sta, true);
}
ewma_avg_signal_init(&mlink->avg_ack_signal);
@@ -1085,6 +1124,8 @@ static void mt7925_mac_link_sta_remove(struct mt76_dev *mdev,
msta = (struct mt792x_sta *)link_sta->sta->drv_priv;
mlink = mt792x_sta_to_link(msta, link_id);
+ if (!mlink)
+ return;
mt7925_roc_abort_sync(dev);
@@ -1098,10 +1139,12 @@ static void mt7925_mac_link_sta_remove(struct mt76_dev *mdev,
link_conf = mt792x_vif_to_bss_conf(vif, link_id);
- if (vif->type == NL80211_IFTYPE_STATION && !link_sta->sta->tdls) {
+ if (link_conf && vif->type == NL80211_IFTYPE_STATION && !link_sta->sta->tdls) {
struct mt792x_bss_conf *mconf;
mconf = mt792x_link_conf_to_mconf(link_conf);
+ if (!mconf)
+ goto out;
if (ieee80211_vif_is_mld(vif))
mt792x_mac_link_bss_remove(dev, mconf, mlink);
@@ -1109,6 +1152,7 @@ static void mt7925_mac_link_sta_remove(struct mt76_dev *mdev,
mt7925_mcu_add_bss_info(&dev->phy, mconf->mt76.ctx, link_conf,
link_sta, false);
}
+out:
spin_lock_bh(&mdev->sta_poll_lock);
if (!list_empty(&mlink->wcid.poll_list))
@@ -1247,22 +1291,22 @@ mt7925_ampdu_action(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
case IEEE80211_AMPDU_RX_START:
mt76_rx_aggr_start(&dev->mt76, &msta->deflink.wcid, tid, ssn,
params->buf_size);
- mt7925_mcu_uni_rx_ba(dev, params, true);
+ ret = mt7925_mcu_uni_rx_ba(dev, params, true);
break;
case IEEE80211_AMPDU_RX_STOP:
mt76_rx_aggr_stop(&dev->mt76, &msta->deflink.wcid, tid);
- mt7925_mcu_uni_rx_ba(dev, params, false);
+ ret = mt7925_mcu_uni_rx_ba(dev, params, false);
break;
case IEEE80211_AMPDU_TX_OPERATIONAL:
mtxq->aggr = true;
mtxq->send_bar = false;
- mt7925_mcu_uni_tx_ba(dev, params, true);
+ ret = mt7925_mcu_uni_tx_ba(dev, params, true);
break;
case IEEE80211_AMPDU_TX_STOP_FLUSH:
case IEEE80211_AMPDU_TX_STOP_FLUSH_CONT:
mtxq->aggr = false;
clear_bit(tid, &msta->deflink.wcid.ampdu_state);
- mt7925_mcu_uni_tx_ba(dev, params, false);
+ ret = mt7925_mcu_uni_tx_ba(dev, params, false);
break;
case IEEE80211_AMPDU_TX_START:
set_bit(tid, &msta->deflink.wcid.ampdu_state);
@@ -1271,8 +1315,9 @@ mt7925_ampdu_action(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
case IEEE80211_AMPDU_TX_STOP_CONT:
mtxq->aggr = false;
clear_bit(tid, &msta->deflink.wcid.ampdu_state);
- mt7925_mcu_uni_tx_ba(dev, params, false);
- ieee80211_stop_tx_ba_cb_irqsafe(vif, sta->addr, tid);
+ ret = mt7925_mcu_uni_tx_ba(dev, params, false);
+ if (!ret)
+ ieee80211_stop_tx_ba_cb_irqsafe(vif, sta->addr, tid);
break;
}
mt792x_mutex_release(dev);
@@ -1293,12 +1338,12 @@ mt7925_mlo_pm_iter(void *priv, u8 *mac, struct ieee80211_vif *vif)
if (mvif->mlo_pm_state != MT792x_MLO_CHANGED_PS)
return;
- mt792x_mutex_acquire(dev);
for_each_set_bit(i, &valid, IEEE80211_MLD_MAX_NUM_LINKS) {
bss_conf = mt792x_vif_to_bss_conf(vif, i);
+ if (!bss_conf)
+ continue;
mt7925_mcu_uni_bss_ps(dev, bss_conf);
}
- mt792x_mutex_release(dev);
}
void mt7925_mlo_pm_work(struct work_struct *work)
@@ -1307,9 +1352,11 @@ void mt7925_mlo_pm_work(struct work_struct *work)
mlo_pm_work.work);
struct ieee80211_hw *hw = mt76_hw(dev);
+ mt792x_mutex_acquire(dev);
ieee80211_iterate_active_interfaces(hw,
IEEE80211_IFACE_ITER_RESUME_ALL,
mt7925_mlo_pm_iter, dev);
+ mt792x_mutex_release(dev);
}
static bool is_valid_alpha2(const char *alpha2)
@@ -1645,6 +1692,8 @@ static void mt7925_ipv6_addr_change(struct ieee80211_hw *hw,
for_each_set_bit(i, &valid, IEEE80211_MLD_MAX_NUM_LINKS) {
bss_conf = mt792x_vif_to_bss_conf(vif, i);
+ if (!bss_conf)
+ continue;
__mt7925_ipv6_addr_change(hw, bss_conf, idev);
}
}
@@ -1706,6 +1755,9 @@ mt7925_conf_tx(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
[IEEE80211_AC_BK] = 1,
};
+ if (!mconf)
+ return -EINVAL;
+
/* firmware uses access class index */
mconf->queue_params[mq_to_aci[queue]] = *params;
@@ -1876,6 +1928,8 @@ static void mt7925_vif_cfg_changed(struct ieee80211_hw *hw,
if (changed & BSS_CHANGED_ARP_FILTER) {
for_each_set_bit(i, &valid, IEEE80211_MLD_MAX_NUM_LINKS) {
bss_conf = mt792x_vif_to_bss_conf(vif, i);
+ if (!bss_conf)
+ continue;
mt7925_mcu_update_arp_filter(&dev->mt76, bss_conf);
}
}
@@ -1891,6 +1945,8 @@ static void mt7925_vif_cfg_changed(struct ieee80211_hw *hw,
} else if (mvif->mlo_pm_state == MT792x_MLO_CHANGED_PS) {
for_each_set_bit(i, &valid, IEEE80211_MLD_MAX_NUM_LINKS) {
bss_conf = mt792x_vif_to_bss_conf(vif, i);
+ if (!bss_conf)
+ continue;
mt7925_mcu_uni_bss_ps(dev, bss_conf);
}
}
@@ -1912,7 +1968,12 @@ static void mt7925_link_info_changed(struct ieee80211_hw *hw,
struct ieee80211_bss_conf *link_conf;
mconf = mt792x_vif_to_link(mvif, info->link_id);
+ if (!mconf)
+ return;
+
link_conf = mt792x_vif_to_bss_conf(vif, mconf->link_id);
+ if (!link_conf)
+ return;
mt792x_mutex_acquire(dev);
@@ -2033,6 +2094,11 @@ mt7925_change_vif_links(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
mlink = mlinks[link_id];
link_conf = mt792x_vif_to_bss_conf(vif, link_id);
+ if (!link_conf) {
+ err = -EINVAL;
+ goto free;
+ }
+
rcu_assign_pointer(mvif->link_conf[link_id], mconf);
rcu_assign_pointer(mvif->sta.link[link_id], mlink);
@@ -2113,9 +2179,14 @@ static int mt7925_assign_vif_chanctx(struct ieee80211_hw *hw,
if (ieee80211_vif_is_mld(vif)) {
mconf = mt792x_vif_to_link(mvif, link_conf->link_id);
+ if (!mconf) {
+ mutex_unlock(&dev->mt76.mutex);
+ return -EINVAL;
+ }
+
pri_link_conf = mt792x_vif_to_bss_conf(vif, mvif->deflink_id);
- if (vif->type == NL80211_IFTYPE_STATION &&
+ if (pri_link_conf && vif->type == NL80211_IFTYPE_STATION &&
mconf == &mvif->bss_conf)
mt7925_mcu_add_bss_info(&dev->phy, NULL, pri_link_conf,
NULL, true);
@@ -2144,6 +2215,10 @@ static void mt7925_unassign_vif_chanctx(struct ieee80211_hw *hw,
if (ieee80211_vif_is_mld(vif)) {
mconf = mt792x_vif_to_link(mvif, link_conf->link_id);
+ if (!mconf) {
+ mutex_unlock(&dev->mt76.mutex);
+ return;
+ }
if (vif->type == NL80211_IFTYPE_STATION &&
mconf == &mvif->bss_conf)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
index 8eda407e4135..cf38e36790e7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
@@ -1722,6 +1722,10 @@ mt7925_mcu_sta_phy_tlv(struct sk_buff *skb,
link_conf = mt792x_vif_to_bss_conf(vif, link_sta->link_id);
mconf = mt792x_vif_to_link(mvif, link_sta->link_id);
+
+ if (!link_conf || !mconf)
+ return;
+
chandef = mconf->mt76.ctx ? &mconf->mt76.ctx->def :
&link_conf->chanreq.oper;
@@ -1800,6 +1804,10 @@ mt7925_mcu_sta_rate_ctrl_tlv(struct sk_buff *skb,
link_conf = mt792x_vif_to_bss_conf(vif, link_sta->link_id);
mconf = mt792x_vif_to_link(mvif, link_sta->link_id);
+
+ if (!link_conf || !mconf)
+ return;
+
chandef = mconf->mt76.ctx ? &mconf->mt76.ctx->def :
&link_conf->chanreq.oper;
band = chandef->chan->band;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
index 8eb1fe1082d1..b6c90c5f7e91 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
@@ -454,7 +454,9 @@ static int mt7925_pci_suspend(struct device *device)
cancel_delayed_work_sync(&pm->ps_work);
cancel_work_sync(&pm->wake_work);
+ mt792x_mutex_acquire(dev);
mt7925_roc_abort_sync(dev);
+ mt792x_mutex_release(dev);
err = mt792x_mcu_drv_pmctrl(dev);
if (err < 0)
@@ -581,10 +583,12 @@ static int _mt7925_pci_resume(struct device *device, bool restore)
}
/* restore previous ds setting */
+ mt792x_mutex_acquire(dev);
if (!pm->ds_enable)
mt7925_mcu_set_deep_sleep(dev, false);
mt7925_regd_update(dev);
+ mt792x_mutex_release(dev);
failed:
pm->suspended = false;
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_core.c b/drivers/net/wireless/mediatek/mt76/mt792x_core.c
index 9cad572c34a3..0170a23b0529 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x_core.c
+++ b/drivers/net/wireless/mediatek/mt76/mt792x_core.c
@@ -95,6 +95,8 @@ void mt792x_tx(struct ieee80211_hw *hw, struct ieee80211_tx_control *control,
IEEE80211_TX_CTRL_MLO_LINK);
sta = (struct mt792x_sta *)control->sta->drv_priv;
mlink = mt792x_sta_to_link(sta, link_id);
+ if (!mlink)
+ goto free_skb;
wcid = &mlink->wcid;
}
@@ -113,9 +115,12 @@ void mt792x_tx(struct ieee80211_hw *hw, struct ieee80211_tx_control *control,
link_id = wcid->link_id;
rcu_read_lock();
conf = rcu_dereference(vif->link_conf[link_id]);
- memcpy(hdr->addr2, conf->addr, ETH_ALEN);
-
link_sta = rcu_dereference(control->sta->link[link_id]);
+ if (!conf || !link_sta) {
+ rcu_read_unlock();
+ goto free_skb;
+ }
+ memcpy(hdr->addr2, conf->addr, ETH_ALEN);
memcpy(hdr->addr1, link_sta->addr, ETH_ALEN);
if (vif->type == NL80211_IFTYPE_STATION)
@@ -136,6 +141,10 @@ void mt792x_tx(struct ieee80211_hw *hw, struct ieee80211_tx_control *control,
}
mt76_connac_pm_queue_skb(hw, &dev->pm, wcid, skb);
+ return;
+
+free_skb:
+ ieee80211_free_txskb(hw, skb);
}
EXPORT_SYMBOL_GPL(mt792x_tx);
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