This is a note to let you know that I've just added the patch titled
ath9k_htc: fix NULL pointer dereference at ath9k_htc_rxep()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ath9k_htc-fix-null-pointer-dereference-at-ath9k_htc_.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f69eff28f9f0bd32e14f0efc12031881ff0dedca
Author: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Tue Sep 21 22:06:23 2021 +0900
ath9k_htc: fix NULL pointer dereference at ath9k_htc_rxep()
[ Upstream commit b0ec7e55fce65f125bd1d7f02e2dc4de62abee34 ]
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: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 0a1634238e673..4f71e962279af 100644
--- 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 */
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
index 8e69e8989f6d3..e7a21eaf3a68d 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
@@ -1130,6 +1130,10 @@ void ath9k_htc_rxep(void *drv_priv, struct sk_buff *skb,
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) {
@@ -1185,6 +1189,10 @@ int ath9k_rx_init(struct ath9k_htc_priv *priv)
list_add_tail(&rxbuf->list, &priv->rx.rxbuf);
}
+ /* Allow ath9k_htc_rxep() to operate. */
+ smp_wmb();
+ priv->rx.initialized = true;
+
return 0;
err:
