From e6b0a7b357659c332231621e4315658d062c23ee Mon Sep 17 00:00:00 2001 From: Charan Teja Kalla Date: Fri, 1 Apr 2022 11:28:12 -0700 Subject: [PATCH] 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/e73da1304a88b6a8a11907045117cccf4c2b8374.1648046642.git.quic_charante@quicinc.com Fixes: 08095d6310a7ce ("mm: madvise: skip unmapped vma holes passed to process_madvise") Signed-off-by: Charan Teja Kalla Acked-by: Michal Hocko Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: David Rientjes Cc: Nadav Amit Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/madvise.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index b41858e..1873616 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1464,16 +1464,9 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, 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); } -- 2.7.4