Re: [PATCH v9 0/10] iommu/vt-d: Fix intel vt-d faults in kdump kernel

Dave Young
2015-05-07T13:25:56Z

On 05/06/15 at 10:16am, Joerg Roedel wrote:
> On Wed, May 06, 2015 at 09:46:49AM +0800, Dave Young wrote:
> > For the original problem, the key issue is dmar faults cause kdump kernel
> > hang so that vmcore can not be saved. I do not know the reason why it hangs
> > I think it is acceptable if kdump kernel boot ok with some dma errors..
>
> It hangs because some devices can't handle the DMAR faults and the kdump
> kernel can't initialize them and will hang itself. For that it doesn't
> matter whether the fault was caused by a read or write request.

Ok, thanks for explanation. so it explains sometimes kdump kernel boot ok
with faults, sometimes it hangs instead.

Dave