[PATCH] Fix a potential NULL pointer deref in znet

[PATCH] Fix a potential NULL pointer deref in znet

[Jesper Juhl]

The coverity checker spotted that we dereference a pointer before we check it
for NULL in drivers/net/znet.c::znet_interrupt().
This fixes the issue.


Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
---

 drivers/net/znet.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

--- linux-2.6.16-rc6-orig/drivers/net/znet.c	2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6.16-rc6/drivers/net/znet.c	2006-03-19 01:08:01.000000000 +0100
@@ -606,17 +606,20 @@ static int znet_send_packet(struct sk_bu
 /* The ZNET interrupt handler. */
 static irqreturn_t znet_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 {
-	struct net_device *dev = dev_id;
-	struct znet_private *znet = dev->priv;
+	struct net_device *dev;
+	struct znet_private *znet;
 	int ioaddr;
 	int boguscnt = 20;
 	int handled = 0;
 
-	if (dev == NULL) {
+	if (dev_id == NULL) {
 		printk(KERN_WARNING "znet_interrupt(): IRQ %d for unknown device.\n", irq);
 		return IRQ_NONE;
 	}
 
+	dev = dev_id;
+	znet = dev->priv;
+
 	spin_lock (&znet->lock);
 	
 	ioaddr = dev->base_addr;


		

Re: [PATCH] Fix a potential NULL pointer deref in znet

[Al Viro]

On Sun, Mar 19, 2006 at 01:12:31AM +0100, Jesper Juhl wrote:
> 
> The coverity checker spotted that we dereference a pointer before we check it
> for NULL in drivers/net/znet.c::znet_interrupt().
> This fixes the issue.

The hell it does.  Either interrupt really isn't shared, in which case
this check should be simply removed, or it can be shared, in which case
the code is still buggered.

Please, stop pulling Bunk - _think_ before submitting "make <program> STFU"
patches.

Re: [PATCH] Fix a potential NULL pointer deref in znet

[Jesper Juhl]

On 3/19/06, Al Viro <viro@ftp.linux.org.uk> wrote:
> On Sun, Mar 19, 2006 at 01:12:31AM +0100, Jesper Juhl wrote:
> >
> > The coverity checker spotted that we dereference a pointer before we check it
> > for NULL in drivers/net/znet.c::znet_interrupt().
> > This fixes the issue.
>
> The hell it does.  Either interrupt really isn't shared, in which case
> this check should be simply removed, or it can be shared, in which case
> the code is still buggered.
>
> Please, stop pulling Bunk - _think_ before submitting "make <program> STFU"
> patches.
>

Believe it or not,  but I actually do try to think about the patches I submit.
I make mistakes sometimes and I don't know all the code in as much
depth as I would like, but I do try to help out the best I can.

I appreciate feedback on the work I do, and I try to improve based on
it - this means I also value your feedback although I must say I
dislike your tone.

I'll stare at the code some more and try to come up with a better
patch after I've had some sleep.

--
Jesper Juhl <jesper.juhl@gmail.com>
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