From 1df726ef0a700587a712a3660b2caa8e533c7de9 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 5 Sep 2011 08:58:29 +0100 Subject: [PATCH] NET: am79c961: fix race in link status code The link status code operates from a timer, and writes the index register without first taking a lock. A well-placed interrupt between writing the index register and reading the data register could change the index register on us, which will return wrong data. Add the necessary lock. Signed-off-by: Russell King --- drivers/net/arm/am79c961a.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/arm/am79c961a.c b/drivers/net/arm/am79c961a.c index 52fe21e..3b1416e 100644 --- a/drivers/net/arm/am79c961a.c +++ b/drivers/net/arm/am79c961a.c @@ -308,8 +308,11 @@ static void am79c961_timer(unsigned long data) struct net_device *dev = (struct net_device *)data; struct dev_priv *priv = netdev_priv(dev); unsigned int lnkstat, carrier; + unsigned long flags; + spin_lock_irqsave(&priv->chip_lock, flags); lnkstat = read_ireg(dev->base_addr, ISALED0) & ISALED0_LNKST; + spin_unlock_irqrestore(&priv->chip_lock, flags); carrier = netif_carrier_ok(dev); if (lnkstat && !carrier) { -- 2.7.4