On Mon, Jun 28, 2021 at 10:46:53AM -0600, Alex Williamson wrote: > On Wed, 10 Mar 2021 11:58:07 -0700 > Alex Williamson <alex.williamson@xxxxxxxxxx> wrote: > > > vfio_pci_mmap_fault() incorrectly makes use of io_remap_pfn_range() > > from within a vm_ops fault handler. This function will trigger a > > BUG_ON if it encounters a populated pte within the remapped range, > > where any fault is meant to populate the entire vma. Concurrent > > inflight faults to the same vma will therefore hit this issue, > > triggering traces such as: If it is just about concurrancy can the vma_lock enclose io_remap_pfn_range() ? > IIRC, there were no blocking issues on this patch as an interim fix to > resolve the concurrent fault issues with io_remap_pfn_range(). > Unfortunately it also got no Reviewed-by or Tested-by feedback. I'd > like to put this in for v5.14 (should have gone in earlier). Any final > comments? Thanks, I assume there is a reason why vm_lock can't be used here, so I wouldn't object, though I don't especially like the loss of tracking either. Jason
