Messages in this thread | | | Date | Sat, 10 Jan 2009 00:16:22 +0800 | From | "Zhao, Yu" <> | Subject | Re: git-latest: kernel oops in IOMMU setup |
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Dirk Hohndel wrote: > On Fri, 9 Jan 2009 14:53:14 +0800 > "Han, Weidong" <weidong.han@intel.com> wrote: > >> Dirk Hohndel wrote: >>> On Thu, 8 Jan 2009 18:05:15 -0800 >>> Dirk Hohndel <hohndel@infradead.org> wrote: >>> >>>> On Fri, 9 Jan 2009 08:58:46 +0800 "Han, Weidong" >>>> >>>> I updated to Linus' latest git (as your description made me wonder >>>> if the async stuff might play a role here). I still get an oops - >>>> but at a different spot and the system no longer hangs - it partly >>>> recovers (but things aren't too well - for example my USB >>>> keyboard / mouse don't work anymore). >>> Spoke too soon. Rebooted and had the same hard lockup again. This >>> time I had my camera within reach, so here's the trace: >>> >>> device_to_iommu+0x33/0x73 >>> domain_context_mapping_one+0x37/0x335 >>> domain_context_mapping+0x25/0xa7 >>> iommu_prepare_identity+0xd7/0xf3 >>> intel_iommu_init+0x4e4/0x8f3 >>> ? mutex_lock >>> ? sysctl_net_init >>> ? pci_iommu_init >>> pci_iommu_init >>> >>> I also have stack, code and register values. Let me know if you need >>> them. Or I can just post the picture :-) >>> >>> Again, very latest git tree, VT-d enabled. >>> >>> /D >> I tried latest git tree, it works for me. Above call trace looks >> right. > > Spent some more time reading the code. Can't quite claim to understand > all of it, yet, but I notice that most everywhere else drhd->devices[i] > is checked to be != NULL before it is accessed. Why is it safe not to > do that in device_to_iommu()? > > Would the patch below be a valid fix? It stops my system from hanging at > boot. But I wonder if there is an assertion that if drhd->ignored is 0 > then drhd->devices[0..drhd->device_cnt] is known to be != NULL and > therefore this test is just hiding a bug somewhere else... > > /D > > Signed-off-by: Dirk Hohndel <hohndel@linux.intel.com> > --- > drivers/pci/intel-iommu.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c > index 235fb7a..3dfecb2 100644 > --- a/drivers/pci/intel-iommu.c > +++ b/drivers/pci/intel-iommu.c > @@ -438,7 +438,8 @@ static struct intel_iommu *device_to_iommu(u8 bus, > u8 devfn) continue; > > for (i = 0; i < drhd->devices_cnt; i++) > - if (drhd->devices[i]->bus->number == bus && > + if (drhd->devices[i] && > + drhd->devices[i]->bus->number == bus && > drhd->devices[i]->devfn == devfn) > return drhd->iommu; >
Did you see following in the kernel message? printk(KERN_WARNING PREFIX "Device scope device [%04x:%02x:%02x.%02x] not found\n", segment, scope->bus, path->dev, path->fn);
If yes, then Acked-by: Yu Zhao <yu.zhao@intel.com>
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