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ath9k_htc: fix NULL pointer dereference at ath9k_htc_rxep()

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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@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+4d2d56175b934b9a7bf9@syzkaller.appspotmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/2b88f416-b2cb-7a18-d688-951e6dc3fe92@i-love.sakura.ne.jp
This commit is contained in:
Tetsuo Handa 2021-09-21 22:06:23 +09:00 committed by Kalle Valo
parent 01e782c891
commit b0ec7e55fc
2 changed files with 9 additions and 0 deletions
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1
drivers/net/wireless/ath/ath9k/htc.h
View file

@ -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 */

8
drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
View file

@ -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: