On Wed, May 06, 2015 at 09:51:35AM +0800, Dave Young wrote: > DMA write will modify system ram, if the old data is corrupted it is possible > that DMA operation modify wrong ram regions because of wrong mapping. > Am I missing something and is it not possible? This might have happened already before the kdump kernel even boots. Also, if there is no IOMMU, this can happen as well. This (unlikely but possible) situation doesn't make things worse. Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html