From: Charan Teja Kalla quic_charante@quicinc.com Subject: Revert "mm: madvise: skip unmapped vma holes passed to process_madvise"

This reverts commit 08095d6310a7 ("mm: madvise: skip unmapped vma holes passed to process_madvise") as process_madvise() fails to return the exact processed bytes in other cases too. As an example: if process_madvise() hits mlocked pages after processing some initial bytes passed in [start, end), it just returns EINVAL although some bytes are processed. Thus making an exception only for ENOMEM is partially fixing the problem of returning the proper advised bytes.

Thus revert this patch and return proper bytes advised.

Link: https://lkml.kernel.org/r/e73da1304a88b6a8a11907045117cccf4c2b8374.164804664... Fixes: 08095d6310a7ce ("mm: madvise: skip unmapped vma holes passed to process_madvise") Signed-off-by: Charan Teja Kalla quic_charante@quicinc.com Acked-by: Michal Hocko mhocko@suse.com Cc: Suren Baghdasaryan surenb@google.com Cc: Vlastimil Babka vbabka@suse.cz Cc: David Rientjes rientjes@google.com Cc: Nadav Amit nadav.amit@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/madvise.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)

--- a/mm/madvise.c~revert-mm-madvise-skip-unmapped-vma-holes-passed-to-process_madvise +++ a/mm/madvise.c @@ -1464,16 +1464,9 @@ SYSCALL_DEFINE5(process_madvise, int, pi

while (iov_iter_count(&iter)) { iovec = iov_iter_iovec(&iter); - /* - * do_madvise returns ENOMEM if unmapped holes are present - * in the passed VMA. process_madvise() is expected to skip - * unmapped holes passed to it in the 'struct iovec' list - * and not fail because of them. Thus treat -ENOMEM return - * from do_madvise as valid and continue processing. - */ ret = do_madvise(mm, (unsigned long)iovec.iov_base, iovec.iov_len, behavior); - if (ret < 0 && ret != -ENOMEM) + if (ret < 0) break; iov_iter_advance(&iter, iovec.iov_len); } _