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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>,
	syzbot+29dc7d4ae19b703ff947@syzkaller.appspotmail.com,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org, linux-usb@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 24/40] usbnet: smsc95xx: Fix use-after-free after removal
Date: Wed,  1 Jul 2020 21:23:45 -0400	[thread overview]
Message-ID: <20200702012402.2701121-24-sashal@kernel.org> (raw)
In-Reply-To: <20200702012402.2701121-1-sashal@kernel.org>

From: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>

[ Upstream commit b835a71ef64a61383c414d6bf2896d2c0161deca ]

Syzbot reports an use-after-free in workqueue context:

BUG: KASAN: use-after-free in mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737
 mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737
 __smsc95xx_mdio_read drivers/net/usb/smsc95xx.c:217 [inline]
 smsc95xx_mdio_read+0x583/0x870 drivers/net/usb/smsc95xx.c:278
 check_carrier+0xd1/0x2e0 drivers/net/usb/smsc95xx.c:644
 process_one_work+0x777/0xf90 kernel/workqueue.c:2274
 worker_thread+0xa8f/0x1430 kernel/workqueue.c:2420
 kthread+0x2df/0x300 kernel/kthread.c:255

It looks like that smsc95xx_unbind() is freeing the structures that are
still in use by the concurrently running workqueue callback. Thus switch
to using cancel_delayed_work_sync() to ensure the work callback really
is no longer active.

Reported-by: syzbot+29dc7d4ae19b703ff947@syzkaller.appspotmail.com
Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/smsc95xx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 355be77f42418..3cf4dc3433f91 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1324,7 +1324,7 @@ static void smsc95xx_unbind(struct usbnet *dev, struct usb_interface *intf)
 	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
 
 	if (pdata) {
-		cancel_delayed_work(&pdata->carrier_check);
+		cancel_delayed_work_sync(&pdata->carrier_check);
 		netif_dbg(dev, ifdown, dev->net, "free pdata\n");
 		kfree(pdata);
 		pdata = NULL;
-- 
2.25.1


      parent reply	other threads:[~2020-07-02  1:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200702012402.2701121-1-sashal@kernel.org>
2020-07-02  1:23 ` [PATCH AUTOSEL 5.4 12/40] net: usb: ax88179_178a: fix packet alignment padding Sasha Levin
2020-07-02  1:23 ` [PATCH AUTOSEL 5.4 17/40] net: ethernet: mvneta: Fix Serdes configuration for SoCs without comphy Sasha Levin
2020-07-02  1:23 ` [PATCH AUTOSEL 5.4 18/40] net: ethernet: mvneta: Add 2500BaseX support " Sasha Levin
2020-07-02  1:23 ` [PATCH AUTOSEL 5.4 19/40] tg3: driver sleeps indefinitely when EEH errors exceed eeh_max_freezes Sasha Levin
2020-07-02  1:23 ` [PATCH AUTOSEL 5.4 20/40] ixgbe: protect ring accesses with READ- and WRITE_ONCE Sasha Levin
2020-07-02  1:23 ` [PATCH AUTOSEL 5.4 21/40] i40e: " Sasha Levin
2020-07-02  1:23 ` [PATCH AUTOSEL 5.4 22/40] ibmvnic: continue to init in CRQ reset returns H_CLOSED Sasha Levin
2020-07-02  1:23 ` Sasha Levin [this message]

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