From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> commit b0ec7e55fce65f125bd1d7f02e2dc4de62abee34 upstream. syzbot is reporting lockdep warning followed by kernel panic at ath9k_htc_rxep() [1], for ath9k_htc_rxep() depends on ath9k_rx_init() being already completed. Since ath9k_htc_rxep() is set by ath9k_htc_connect_svc(WMI_BEACON_SVC) from ath9k_init_htc_services(), it is possible that ath9k_htc_rxep() is called via timer interrupt before ath9k_rx_init() from ath9k_init_device() is called. Since we can't call ath9k_init_device() before ath9k_init_htc_services(), let's hold ath9k_htc_rxep() no-op until ath9k_rx_init() completes. Link: https://syzkaller.appspot.com/bug?extid=4d2d56175b934b9a7bf9 [1] Reported-by: syzbot <syzbot+4d2d56175b934b9a7bf9@xxxxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Tested-by: syzbot <syzbot+4d2d56175b934b9a7bf9@xxxxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx> Link: https://lore.kernel.org/r/2b88f416-b2cb-7a18-d688-951e6dc3fe92@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 | 8 ++++++++ 2 files changed, 9 insertions(+) --- a/drivers/net/wireless/ath/ath9k/htc.h +++ b/drivers/net/wireless/ath/ath9k/htc.h @@ -281,6 +281,7 @@ struct ath9k_htc_rxbuf { struct ath9k_htc_rx { struct list_head rxbuf; spinlock_t rxbuflock; + bool initialized; }; #define ATH9K_HTC_TX_CLEANUP_INTERVAL 50 /* ms */ --- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c +++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c @@ -1133,6 +1133,10 @@ void ath9k_htc_rxep(void *drv_priv, stru struct ath9k_htc_rxbuf *rxbuf = NULL, *tmp_buf = NULL; unsigned long flags; + /* Check if ath9k_rx_init() completed. */ + if (!data_race(priv->rx.initialized)) + goto err; + spin_lock_irqsave(&priv->rx.rxbuflock, flags); list_for_each_entry(tmp_buf, &priv->rx.rxbuf, list) { if (!tmp_buf->in_process) { @@ -1188,6 +1192,10 @@ int ath9k_rx_init(struct ath9k_htc_priv list_add_tail(&rxbuf->list, &priv->rx.rxbuf); } + /* Allow ath9k_htc_rxep() to operate. */ + smp_wmb(); + priv->rx.initialized = true; + return 0; err:
