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Subject[PATCH][RESEND] Avoid possible NULL pointer deref in 3c359 driver
Date
(Resending old patch originally submitted at 1/7-2007 02:19)


In xl_freemem(), if dev_if is NULL, the line
struct xl_private *xl_priv =(struct xl_private *)dev->priv;
will cause a NULL pointer dereference. However, if we move
that assignment below the 'if' statement that tests for a NULL
'dev', then that NULL deref can never happen.
It never hurts to be safe :-)


Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
---
diff --git a/drivers/net/tokenring/3c359.c b/drivers/net/tokenring/3c359.c
index e22a3f5..671f4da 100644
--- a/drivers/net/tokenring/3c359.c
+++ b/drivers/net/tokenring/3c359.c
@@ -1044,15 +1044,17 @@ static void xl_freemem(struct net_device *dev)
static irqreturn_t xl_interrupt(int irq, void *dev_id)
{
struct net_device *dev = (struct net_device *)dev_id;
- struct xl_private *xl_priv =(struct xl_private *)dev->priv;
- u8 __iomem * xl_mmio = xl_priv->xl_mmio ;
- u16 intstatus, macstatus ;
+ struct xl_private *xl_priv;
+ u8 __iomem * xl_mmio;
+ u16 intstatus, macstatus;

if (!dev) {
- printk(KERN_WARNING "Device structure dead, aaahhhh !\n") ;
+ printk(KERN_WARNING "3c359: Device structure dead, aaahhhh!\n");
return IRQ_NONE;
}

+ xl_priv = (struct xl_private *)dev->priv;
+ xl_mmio = xl_priv->xl_mmio;
intstatus = readw(xl_mmio + MMIO_INTSTATUS) ;

if (!(intstatus & 1)) /* We didn't generate the interrupt */


-
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