Messages in this thread | | | Date | Thu, 9 Apr 2009 21:59:02 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] skge: fix occasional BUG during MTU change |
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On Tue, 7 Apr 2009 18:36:23 +0200 Michal Schmidt <mschmidt@redhat.com> wrote:
> The BUG_ON(skge->tx_ring.to_use != skge->tx_ring.to_clean) in skge_up() > was sometimes observed when setting MTU. > > skge_down() disables the TX queue, but then reenables it by mistake via > skge_tx_clean(). > Fix it by moving the waking of the queue from skge_tx_clean() to the > other caller. And to make sure start_xmit is not in progress on another > CPU, skge_down() should call netif_tx_disable(). > > The bug was reported to me by Jiri Jilek whose Debian system sometimes > failed to boot. He tested the patch and the bug did not happen anymore.
It's conventional to add the reporter's "Reported-by:" tag to the changelog in this situation.
> Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
As the bug is present in 2.6.29 (and possibly earlier?) it's appropriate to add a Cc: <stable@kernel.org> too. This makes davem go mad at you, but I prefer getting madded at over possibly losing bugfixes ;)
> > diff --git a/drivers/net/skge.c b/drivers/net/skge.c > index 952d37f..b2a05af 100644 > --- a/drivers/net/skge.c > +++ b/drivers/net/skge.c > @@ -2674,7 +2674,7 @@ static int skge_down(struct net_device *dev) > if (netif_msg_ifdown(skge)) > printk(KERN_INFO PFX "%s: disabling interface\n", dev->name); > > - netif_stop_queue(dev); > + netif_tx_disable(dev); > > if (hw->chip_id == CHIP_ID_GENESIS && hw->phy_type == SK_PHY_XMAC) > del_timer_sync(&skge->link_timer); > @@ -2881,7 +2881,6 @@ static void skge_tx_clean(struct net_device *dev) > } > > skge->tx_ring.to_clean = e; > - netif_wake_queue(dev); > } > > static void skge_tx_timeout(struct net_device *dev) > @@ -2893,6 +2892,7 @@ static void skge_tx_timeout(struct net_device *dev) > > skge_write8(skge->hw, Q_ADDR(txqaddr[skge->port], Q_CSR), CSR_STOP); > skge_tx_clean(dev); > + netif_wake_queue(dev); > } > > static int skge_change_mtu(struct net_device *dev, int new_mtu)
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