Messages in this thread | | | Date | Thu, 21 Jan 2010 21:41:33 +0100 | From | Jarek Poplawski <> | Subject | Re: [PATCH] sky2: Fix WARNING: at lib/dma-debug.c:902 check_sync |
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On Thu, Jan 21, 2010 at 02:59:19PM -0500, Michael Breuer wrote: > On 1/20/2010 4:41 AM, Jarek Poplawski wrote: > >[ previously: Re: [PATCH] af_packet: Don't use skb after dev_queue_xmit() ] > >diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c > >index 7650f73..cdebdd3 100644 > >--- a/drivers/net/sky2.c > >+++ b/drivers/net/sky2.c > >@@ -2252,12 +2252,14 @@ static struct sk_buff *receive_copy(struct sky2_port *sky2, > > skb = netdev_alloc_skb_ip_align(sky2->netdev, length); > > if (likely(skb)) { > > pci_dma_sync_single_for_cpu(sky2->hw->pdev, re->data_addr, > >- length, PCI_DMA_FROMDEVICE); > >+ pci_unmap_len(re, data_size), > >+ PCI_DMA_FROMDEVICE); > > skb_copy_from_linear_data(re->skb, skb->data, length); > > skb->ip_summed = re->skb->ip_summed; > > skb->csum = re->skb->csum; > > pci_dma_sync_single_for_device(sky2->hw->pdev, re->data_addr, > >- length, PCI_DMA_FROMDEVICE); > >+ pci_unmap_len(re, data_size), > >+ PCI_DMA_FROMDEVICE); > > re->skb->ip_summed = CHECKSUM_NONE; > > skb_put(skb, length); > > } > Just a testing update: I went back to CONFIG_DMAR=Y yesterday and > have not (yet) encountered the sky2 crash I'd been having prior to > this fix. I've been pumping traffic through, and based on pre-patch > experience, it would likely have crashed by now. > > Will keep the system up for the next couple of days w/o reboot to > confirm that the sky2 lockup I'd been seeing has stopped happening > with this patch. > > Test notes: > > 1) Warning previously apparent on start (dma_debug check_sync) with > CONFIG_DMAR=n is gone. > 2) W/o the above patch, I was getting sky2 DMAR errors and > subsequent TX hangs requiring reboot to clear. The hangs happened > after at least 12 hours of uptime, and under RX load at the time of > the hang. > 3) With the above patch (and no other changes) I have not been able > to recreate the crash - the system is stable.
Btw, could you remind us if during last dmar bugs jumbo frames might have been used or maybe mtu was changed, and the current test setting?
> > I have been following the discussion about the DMA api would suggest > that the length issue when DMAR is enabled is less innocuous than > previously believed.
Actually, the last conclusions are - it's more innocuous than ever believed, and I completely agree with this (at least until the next week ;-).
Thanks, Jarek P.
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