On Mon, Mar 08, 2010 at 03:32:19PM +0200, Avi Kivity wrote: > It looks unrelated to kvm, though of course random memory corruption > cannot be ruled out. > > Is npt enabled on the host (cat /sys/module/kvm_amd/parameters/npt)? > > Andrea, any idea?
Basically find_vma(vma->vm_mm, vma->vm_start) doesn't return "vma" despite "vma" is the one with the smaller vm_end where the comparison "vma->vm_start < vma->vm_end" is true (the next vma is null and the prev will have vma->vm_start == prev->vm_end, not <). The bug check looks right, it doesn't seem false positive and this bugcheck indicates that the vma rbtree is memory-corrupted somehow. so yes fiddling with npt on and off sounds a good start, if it's a bug in shadow paging it's unlikely the exact same bug materializes with both npt and without. If the crash happens with npt on and off, then maybe it's not hypervisor related. Could also be bad RAM if it only happens on a single host and all other hosts are fine with same binary guest/host kernels (rbtree walk might stress the memory bus more than other operations). Said that vm_next being null (and if it's null, likely vm_next pointer has no ram bitflip) is a bit weird and not common scenario and this page fault seems triggered with procfs copy_user call which is non standard, so maybe this is a guest bug. It would be interesting to know what is the vm_start address, at the end there are stack, vdso and vsyscall areas. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
