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* kernel BUG at drivers/net/phy/mdio_bus.c:165!
@ 2008-12-17  2:29 Krzysztof Halasa
  2008-12-17  8:24 ` David Miller
  0 siblings, 1 reply; 2+ messages in thread
From: Krzysztof Halasa @ 2008-12-17  2:29 UTC (permalink / raw)
  To: Lennert Buytenhek; +Cc: David Miller, netdev

kernel BUG at drivers/net/phy/mdio_bus.c:165!
Unable to handle kernel NULL pointer dereference at virtual address 00000000

How?

mdiobus_alloc() sets bus->state = MDIOBUS_ALLOCATED.

mdiobus_register() sets bus->state = MDIOBUS_REGISTERED but then can
   fail (mdiobus_scan()) returning an error to the caller.

The caller aborts correctly with mdiobus_free() which does:
        if (bus->state == MDIOBUS_ALLOCATED) {
                kfree(bus);
                return;
        }

        BUG_ON(bus->state != MDIOBUS_UNREGISTERED);

Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>

--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -105,8 +105,6 @@ int mdiobus_register(struct mii_bus *bus)
 		return -EINVAL;
 	}
 
-	bus->state = MDIOBUS_REGISTERED;
-
 	mutex_init(&bus->mdio_lock);
 
 	if (bus->reset)
@@ -123,6 +121,9 @@ int mdiobus_register(struct mii_bus *bus)
 		}
 	}
 
+	if (!err)
+		bus->state = MDIOBUS_REGISTERED;
+
 	pr_info("%s: probed\n", bus->name);
 
 	return err;

-- 
Krzysztof Halasa

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: kernel BUG at drivers/net/phy/mdio_bus.c:165!
  2008-12-17  2:29 kernel BUG at drivers/net/phy/mdio_bus.c:165! Krzysztof Halasa
@ 2008-12-17  8:24 ` David Miller
  0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2008-12-17  8:24 UTC (permalink / raw)
  To: khc; +Cc: buytenh, netdev

From: Krzysztof Halasa <khc@pm.waw.pl>
Date: Wed, 17 Dec 2008 03:29:46 +0100

> kernel BUG at drivers/net/phy/mdio_bus.c:165!
> Unable to handle kernel NULL pointer dereference at virtual address 00000000
> 
> How?
> 
> mdiobus_alloc() sets bus->state = MDIOBUS_ALLOCATED.
> 
> mdiobus_register() sets bus->state = MDIOBUS_REGISTERED but then can
>    fail (mdiobus_scan()) returning an error to the caller.
> 
> The caller aborts correctly with mdiobus_free() which does:
>         if (bus->state == MDIOBUS_ALLOCATED) {
>                 kfree(bus);
>                 return;
>         }
> 
>         BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
> 
> Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>

Looks great, applied.

Thanks for fixing this bug Krzysztof.

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2008-12-17  8:24 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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2008-12-17  2:29 kernel BUG at drivers/net/phy/mdio_bus.c:165! Krzysztof Halasa
2008-12-17  8:24 ` David Miller

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