On Wed, Jul 12, 2023 at 07:48:06PM +0000, Suren Baghdasaryan wrote: > > Would we be able to fix it in stable simply by not triggering the > > vm_flags_set() in case these flags are already set? > > I think we can do that. gru_file_mmap() sets all the flags that are > set by remap_pfn_range_notrack() (VM_IO | VM_PFNMAP | VM_DONTEXPAND | > VM_DONTDUMP), so we can check if all bits are already present and skip > the vm_flags_set() call. > But on x86, remap_pfn_range() also sets flag VM_PAT. (in track_pfn_remap()). Is there any interface to allow device driver to pre-set this flag in .mmap() before .fault()? e.g. export track_pfn_remap() ?
