Messages in this thread |  | | | Date | Thu, 20 Nov 2008 12:31:29 +0100 | | From | Joerg Roedel <> | | Subject | Re: [GIT PULL] AMD IOMMU updates for 2.6.28-rc5 |
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On Thu, Nov 20, 2008 at 01:25:15PM +0900, FUJITA Tomonori wrote: > On Wed, 19 Nov 2008 10:25:44 +0100 > Joerg Roedel <joro@8bytes.org> wrote: > > I found issues in network drivers only for now. The two drivers where I > > found issues are the in-kernel ixgbe driver (I see IO_PAGE_FAULTS > > there), the ixgbe version from the Intel website has a double-free bug > > when unloading the driver or changing the device mtu. The same problem > > was found with the Broadcom NetXtreme II driver. > > I see, thanks. You already reported the bugs to netdev? >
Not yet, but I will do so when I can prove the bug is not in my driver ;) (== when my debug code is ready)
> > We can't test all drivers for those bugs until 2.6.28 will be released. > > And these bugs can corrupt data, for example when a driver frees dma > > addresses allocated by another driver and these addresses are then > > reallocated. > > The only way to protect the drivers from each other is to isolate them > > in different protection domains. The AMD IOMMU driver prints a WARN_ON() > > if a driver frees dma addresses not yet mapped. This triggered with the > > bnx2 and the ixgbe driver. > > It would be better to add such WARN_ON to VT-d. VT-d is everywhere > nowadays. I think that there are some developers who can test these > drivers with VT-d.
Yes, I agree.
> > And the data corruption is real, it eat the root-fs of my testbox one > > time. > > I agree that we need to fix the drivers. I plan to implement some debug > > code which allows driver developers to detect those bugs even if they > > have no IOMMU in the system. > > It's not so hard to add such debug feature to swiotlb, I guess. >
Yes, but I prefer to have it outside of any dma_ops implementation. This way it can also be used to find out if a bug originated from the device driver or the dma_ops implementation.
Joerg
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