[ldv-project] Patch "ath9k_htc: fix NULL pointer dereference at ath9k_htc_tx_get_packet()" has been added to the 5.10-stable tree

[gregkh at linuxfoundation.org]

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_tx_get_packet()

to the 5.10-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_tx_get_packet.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.


>From foo at baz Wed Aug  3 01:49:25 PM CEST 2022
From: Fedor Pchelkin <pchelkin at ispras.ru>
Date: Mon,  1 Aug 2022 18:59:08 +0300
Subject: ath9k_htc: fix NULL pointer dereference at ath9k_htc_tx_get_packet()
To: stable at vger.kernel.org, Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Cc: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>, Kalle Valo <quic_kvalo at quicinc.com>, Alexey Khoroshilov <khoroshilov at ispras.ru>, ldv-project at linuxtesting.org, syzbot <syzbot+31d54c60c5b254d6f75b at syzkaller.appspotmail.com>, Fedor Pchelkin <pchelkin at ispras.ru>
Message-ID: <20220801155908.1539833-3-pchelkin at ispras.ru>

From: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>

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 at syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+31d54c60c5b254d6f75b at syzkaller.appspotmail.com>
Signed-off-by: Kalle Valo <quic_kvalo at quicinc.com>
Link: https://lore.kernel.org/r/77b76ac8-2bee-6444-d26c-8c30858b8daa@i-love.sakura.ne.jp
Signed-off-by: Fedor Pchelkin <pchelkin at ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 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);


Patches currently in stable-queue which might be from pchelkin at ispras.ru are

queue-5.10/ath9k_htc-fix-null-pointer-dereference-at-ath9k_htc_tx_get_packet.patch
queue-5.10/ath9k_htc-fix-null-pointer-dereference-at-ath9k_htc_rxep.patch