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
