From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> commit 8b3046abc99eefe11438090bcc4ec3a3994b55d0 upstream. syzbot is reporting lockdep warning at ath9k_wmi_event_tasklet() followed by kernel panic at get_htc_epid_queue() from ath9k_htc_tx_get_packet() from ath9k_htc_txstatus() [1], for ath9k_wmi_event_tasklet(WMI_TXSTATUS_EVENTID) depends on spin_lock_init() from ath9k_init_priv() being already completed. Since ath9k_wmi_event_tasklet() is set by ath9k_init_wmi() from ath9k_htc_probe_device(), it is possible that ath9k_wmi_event_tasklet() is called via tasklet interrupt before spin_lock_init() from ath9k_init_priv() from ath9k_init_device() from ath9k_htc_probe_device() is called. Let's hold ath9k_wmi_event_tasklet(WMI_TXSTATUS_EVENTID) no-op until ath9k_tx_init() completes. Link: https://syzkaller.appspot.com/bug?extid=31d54c60c5b254d6f75b [1] Reported-by: syzbot <syzbot+31d54c60c5b254d6f75b@xxxxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Tested-by: syzbot <syzbot+31d54c60c5b254d6f75b@xxxxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx> Link: https://lore.kernel.org/r/77b76ac8-2bee-6444-d26c-8c30858b8daa@xxxxxxxxxxxxxxxxxxx Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/ath/ath9k/htc.h | 1 + drivers/net/wireless/ath/ath9k/htc_drv_txrx.c | 5 +++++ drivers/net/wireless/ath/ath9k/wmi.c | 4 ++++ 3 files changed, 10 insertions(+) --- a/drivers/net/wireless/ath/ath9k/htc.h +++ b/drivers/net/wireless/ath/ath9k/htc.h @@ -306,6 +306,7 @@ struct ath9k_htc_tx { DECLARE_BITMAP(tx_slot, MAX_TX_BUF_NUM); struct timer_list cleanup_timer; spinlock_t tx_lock; + bool initialized; }; struct ath9k_htc_tx_ctl { --- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c +++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c @@ -808,6 +808,11 @@ int ath9k_tx_init(struct ath9k_htc_priv skb_queue_head_init(&priv->tx.data_vi_queue); skb_queue_head_init(&priv->tx.data_vo_queue); skb_queue_head_init(&priv->tx.tx_failed); + + /* Allow ath9k_wmi_event_tasklet(WMI_TXSTATUS_EVENTID) to operate. */ + smp_wmb(); + priv->tx.initialized = true; + return 0; } --- a/drivers/net/wireless/ath/ath9k/wmi.c +++ b/drivers/net/wireless/ath/ath9k/wmi.c @@ -169,6 +169,10 @@ void ath9k_wmi_event_tasklet(struct task &wmi->drv_priv->fatal_work); break; case WMI_TXSTATUS_EVENTID: + /* Check if ath9k_tx_init() completed. */ + if (!data_race(priv->tx.initialized)) + break; + spin_lock_bh(&priv->tx.tx_lock); if (priv->tx.flags & ATH9K_HTC_OP_TX_DRAIN) { spin_unlock_bh(&priv->tx.tx_lock);
