syzbot is reporting NULL pointer dereference 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 <[email protected]>
Signed-off-by: Tetsuo Handa <[email protected]>
Tested-by: [email protected]
---
drivers/net/wireless/ath/ath9k/htc.h | 1 +
drivers/net/wireless/ath/ath9k/htc_drv_txrx.c | 3 +++
drivers/net/wireless/ath/ath9k/wmi.c | 3 +++
3 files changed, 7 insertions(+)
diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 4f71e962279a..6b45e63fae4b 100644
--- 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 {
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
index 0d4595ee51ba..a5240a7f8c00 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
@@ -813,6 +813,9 @@ int ath9k_tx_init(struct ath9k_htc_priv *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;
}
diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c
index fe29ad4b9023..7e17d86bf5d3 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.c
+++ b/drivers/net/wireless/ath/ath9k/wmi.c
@@ -169,6 +169,9 @@ void ath9k_wmi_event_tasklet(struct tasklet_struct *t)
&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);
--
2.30.2