Subject: Re: tg3: unable to handle null pointer dereference [Re: Linux 2.6.21-rc6]

From: "Michael Chan" <[email-masked]>
Date: Fri, 06 Apr 2007 15:57:13 -0700

On Fri, 2007-04-06 at 14:40 -0700, Nishanth Aravamudan wrote:

> 2.6.21-rc5 is ok. 2.6.21-rc6 results in
> 
> [   14.241665] Unable to handle kernel NULL pointer dereference (address 0000000000000000)

Sorry, I think this should fix it:

[TG3]: Fix crash during tg3_init_one().

The driver will crash when the chip has been initialized by EFI before
tg3_init_one().  In this case, the driver will call tg3_chip_reset()
before allocating consistent memory.

The bug is fixed by checking for tp->hw_status before accessing it
during tg3_chip_reset().

Signed-off-by: Michael Chan <[email-masked]>

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index 0acee9f..256969e 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -4834,8 +4834,10 @@ static int tg3_chip_reset(struct tg3 *tp)
 	 * sharing or irqpoll.
 	 */
 	tp->tg3_flags |= TG3_FLAG_CHIP_RESETTING;
-	tp->hw_status->status = 0;
-	tp->hw_status->status_tag = 0;
+	if (tp->hw_status) {
+		tp->hw_status->status = 0;
+		tp->hw_status->status_tag = 0;
+	}
 	tp->last_tag = 0;
 	smp_mb();
 	synchronize_irq(tp->pdev->irq);