2008-03-23 09:11:16

by Marin Mitov

Subject: [PATCH]skge napi->poll() locking bug

Hi all,

According to: Documentation/networking/netdevices.txt:

<cite>
napi->poll:
..........
Context: softirq
will be called with interrupts disabled by netconsole.
</cite>

napi->poll() could be called either with interrupts enabled
(in softirq context) or disabled (by netconsole), so the irq flag
should be preserved.

Inspired by Ingo's resent forcedeth patch :-)

Regards

Marin Mitov

Signed-off-by: Marin Mitov <[email protected]>
===============================
--- a/drivers/net/skge.c 2008-03-23 09:06:13.000000000 +0200
+++ b/drivers/net/skge.c 2008-03-23 09:24:47.000000000 +0200
@@ -3199,12 +3199,14 @@ static int skge_poll(struct napi_struct
skge_write8(hw, Q_ADDR(rxqaddr[skge->port], Q_CSR), CSR_START);

if (work_done < to_do) {
- spin_lock_irq(&hw->hw_lock);
+ unsigned long flags;
+
+ spin_lock_irqsave(&hw->hw_lock, flags);
__netif_rx_complete(dev, napi);
hw->intr_mask |= napimask[skge->port];
skge_write32(hw, B0_IMSK, hw->intr_mask);
skge_read32(hw, B0_IMSK);
- spin_unlock_irq(&hw->hw_lock);
+ spin_unlock_irqrestore(&hw->hw_lock, flags);
}

return work_done;

2008-03-23 10:19:46

by David Miller

Subject: Re: [PATCH]skge napi->poll() locking bug

From: Marin Mitov <[email protected]>
Date: Sun, 23 Mar 2008 10:20:09 +0200

Please send networking things at least CC:'d to netdev
as many networking developers do not subscribe to
linux-kernel

> According to: Documentation/networking/netdevices.txt:
>
> <cite>
> napi->poll:
> ..........
> Context: softirq
> will be called with interrupts disabled by netconsole.
> </cite>
>
> napi->poll() could be called either with interrupts enabled
> (in softirq context) or disabled (by netconsole), so the irq flag
> should be preserved.
>
> Inspired by Ingo's resent forcedeth patch :-)
>
> Regards
>
> Marin Mitov
>
> Signed-off-by: Marin Mitov <[email protected]>

Acked-by: David S. Miller <[email protected]>

2008-03-26 03:21:00

by Jeff Garzik

Subject: Re: [PATCH]skge napi->poll() locking bug

Marin Mitov wrote:
> Hi all,
>
> According to: Documentation/networking/netdevices.txt:
>
> <cite>
> napi->poll:
> ..........
> Context: softirq
> will be called with interrupts disabled by netconsole.
> </cite>
>
> napi->poll() could be called either with interrupts enabled
> (in softirq context) or disabled (by netconsole), so the irq flag
> should be preserved.
>
> Inspired by Ingo's resent forcedeth patch :-)
>
> Regards
>
> Marin Mitov
>
> Signed-off-by: Marin Mitov <[email protected]>
> ===============================
> --- a/drivers/net/skge.c 2008-03-23 09:06:13.000000000 +0200
> +++ b/drivers/net/skge.c 2008-03-23 09:24:47.000000000 +0200
> @@ -3199,12 +3199,14 @@ static int skge_poll(struct napi_struct
> skge_write8(hw, Q_ADDR(rxqaddr[skge->port], Q_CSR), CSR_START);
>
> if (work_done < to_do) {
> - spin_lock_irq(&hw->hw_lock);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&hw->hw_lock, flags);
> __netif_rx_complete(dev, napi);
> hw->intr_mask |= napimask[skge->port];
> skge_write32(hw, B0_IMSK, hw->intr_mask);
> skge_read32(hw, B0_IMSK);
> - spin_unlock_irq(&hw->hw_lock);
> + spin_unlock_irqrestore(&hw->hw_lock, flags);
> }
>
> return work_done;
>
>
> --

applied