On Wed, Oct 02, 2019 at 03:47:24PM +0200, Thomas Hellström (VMware) wrote: > From: Thomas Hellstrom <[email protected]> > > The caller needs to make sure that the vma is not torn down during the > lock operation and can also use the i_mmap_rwsem for file-backed vmas. > Remove the BUG_ON. We could, as an alternative, add a test that either > vma->vm_mm->mmap_sem or vma->vm_file->f_mapping->i_mmap_rwsem are held. > > Cc: Andrew Morton <[email protected]> > Cc: Matthew Wilcox <[email protected]> > Cc: Will Deacon <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Rik van Riel <[email protected]> > Cc: Minchan Kim <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Huang Ying <[email protected]> > Cc: Jérôme Glisse <[email protected]> > Cc: Kirill A. Shutemov <[email protected]> > Signed-off-by: Thomas Hellstrom <[email protected]>
The patch looks good to me: Acked-by: Kirill A. Shutemov <[email protected]> But I looked at usage at pagewalk.c and it is inconsitent. The walker takes ptl before calling ->pud_entry(), but not for ->pmd_entry(). It should be fixed: do not take the lock before ->pud_entry(). The callback must take care of it. Looks like we have single ->pud_entry() implementation the whole kernel. It should be trivial to fix. Could you do this? -- Kirill A. Shutemov
