[patch, -rc5-mm3] lock validator: fix ns83820.c irq-flags part 3

[Arjan van de Ven]

On Sun, 2006-06-04 at 02:53 -0700, Barry K. Nathan wrote:
> On 6/4/06, Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> wrote:
> > just the preempt the next email from Barry; while fixing this one I
> > looked at the usage of the locks more and found another patch needed...
> [snip]
> 
> Nice try, but it didn't work. ~_^
> 
> I was about to reply to the previous ns83820 patch with my dmesg, when
> I saw this one. I applied this patch too, and like the previous patch,
> it reports an instance of illegal lock usage. My dmesg follows.
> -- 


ok this is a real driver deadlock:

The ns83820 driver enabled interrupts (by unlocking the misc_lock with
_irq) while still holding the rx_info.lock, which is required to be irq
safe since it's used in the ISR like this:
                writel(1, dev->base + IER);
                spin_unlock_irq(&dev->misc_lock);
                kick_rx(ndev);
                spin_unlock_irq(&dev->rx_info.lock);

This is can cause a deadlock if an irq was pending at the first
spin_unlock_irq already, or if one would hit during kick_rx(). 
Simply remove the first _irq solves this

Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>


---
 drivers/net/ns83820.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.17-rc5-mm3/drivers/net/ns83820.c
===================================================================
--- linux-2.6.17-rc5-mm3.orig/drivers/net/ns83820.c
+++ linux-2.6.17-rc5-mm3/drivers/net/ns83820.c
@@ -808,7 +808,7 @@ static int ns83820_setup_rx(struct net_d
 
 		writel(dev->IMR_cache, dev->base + IMR);
 		writel(1, dev->base + IER);
-		spin_unlock_irq(&dev->misc_lock);
+		spin_unlock(&dev->misc_lock);
 
 		kick_rx(ndev);
 

-
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