Subject: [PATCH] hdlcdrv: fix divide error bug if bitrate is 0

From: Firo Yang <[email-masked]>
Date: Wed, 17 May 2017 20:35:49 +0800

The divisor s->par.bitrate will always be 0 until initialized by
ndo_open() and hdlcdrv_open().

In order to fix this divide zero error, check whether the netdevice
was opened by ndo_open() before performing divide.

Reported-by: Dmitry Vyukov <[email-masked]>
Signed-off-by: Firo Yang <[email-masked]>
---
 drivers/net/hamradio/hdlcdrv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c
index 8c3633c..3c783fd 100644
--- a/drivers/net/hamradio/hdlcdrv.c
+++ b/drivers/net/hamradio/hdlcdrv.c
@@ -574,7 +574,7 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 		break;		
 
 	case HDLCDRVCTL_CALIBRATE:
-		if(!capable(CAP_SYS_RAWIO))
+		if (!capable(CAP_SYS_RAWIO) || !netif_running(dev))
 			return -EPERM;
 		if (bi.data.calibrate > INT_MAX / s->par.bitrate)
 			return -EINVAL;
-- 
2.9.4