[PATCH AUTOSEL 4.4 23/25] net/usb: cancel pending work when unbinding smsc75xx

Sasha Levin
2018-10-16T04:16:46Z

From: Yu Zhao <yuzhao@google.com>

[ Upstream commit f7b2a56e1f3dcbdb4cf09b2b63e859ffe0e09df8 ]

Cancel pending work before freeing smsc75xx private data structure
during binding. This fixes the following crash in the driver:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000050
IP: mutex_lock+0x2b/0x3f
<snipped>
Workqueue: events smsc75xx_deferred_multicast_write [smsc75xx]
task: ffff8caa83e85700 task.stack: ffff948b80518000
RIP: 0010:mutex_lock+0x2b/0x3f
<snipped>
Call Trace:
smsc75xx_deferred_multicast_write+0x40/0x1af [smsc75xx]
process_one_work+0x18d/0x2fc
worker_thread+0x1a2/0x269
? pr_cont_work+0x58/0x58
kthread+0xfa/0x10a
? pr_cont_work+0x58/0x58
? rcu_read_unlock_sched_notrace+0x48/0x48
ret_from_fork+0x22/0x40

Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/usb/smsc75xx.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c
index 1a8b9ea49144..234febc6e1d9 100644
--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -1509,6 +1509,7 @@ static void smsc75xx_unbind(struct usbnet *dev, struct usb_interface *intf)
{
struct smsc75xx_priv *pdata = (struct smsc75xx_priv *)(dev->data[0]);
if (pdata) {
+ cancel_work_sync(&pdata->set_multicast);
netif_dbg(dev, ifdown, dev->net, "free pdata\n");
kfree(pdata);
pdata = NULL;
--
2.17.1