On Wed, Jan 28, 2026 at 09:38:37AM -0700, Nico Pache wrote: > Hi Andrew, > > could you please apply the following fixup to avoid potentially using a stale > VMA in the new writeback-retry logic for madvise collapse. > > Thank you! > -- Nico > > ----8<---- > commit a9ac3b1bfa926dd707ac3a785583f8d7a0579578 > Author: Nico Pache <[email protected]> > Date: Fri Jan 23 16:32:42 2026 -0700 > > madvise writeback retry logic fix > > Signed-off-by: Nico Pache <[email protected]> > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 59e5a5588d85..2b054f7d9753 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -2418,6 +2418,14 @@ static enum scan_result collapse_single_pmd(unsigned > long > addr, > mmap_read_unlock(mm); > *mmap_locked = false; > result = collapse_scan_file(mm, addr, file, pgoff, cc); > + > + if (!cc->is_khugepaged && result == SCAN_PAGE_DIRTY_OR_WRITEBACK && > + mapping_can_writeback(file->f_mapping)) { > + const loff_t lstart = (loff_t)pgoff << PAGE_SHIFT; > + const loff_t lend = lstart + HPAGE_PMD_SIZE - 1; > + > + filemap_write_and_wait_range(file->f_mapping, lstart, lend); > + } > fput(file); > > if (result != SCAN_PTE_MAPPED_HUGEPAGE) > @@ -2840,19 +2848,8 @@ int madvise_collapse(struct vm_area_struct *vma, > unsigned > long start, > *lock_dropped = true; > > if (result == SCAN_PAGE_DIRTY_OR_WRITEBACK && !triggered_wb) { > - struct file *file = get_file(vma->vm_file); > - pgoff_t pgoff = linear_page_index(vma, addr); > - > - if (mapping_can_writeback(file->f_mapping)) { > - loff_t lstart = (loff_t)pgoff << PAGE_SHIFT; > - loff_t lend = lstart + HPAGE_PMD_SIZE - 1; > - > - filemap_write_and_wait_range(file->f_mapping, > lstart, lend); > - triggered_wb = true; > - fput(file); > - goto retry; > - } > - fput(file); > + triggered_wb = true; > + goto retry; > }
LGTM, with this in place you can add back my tag to the patch. It'd be good to reference this in the commit message, but you can do that on a respin. So: Reviewed-by: Lorenzo Stoakes <[email protected]>
