[CRIU] [PATCH 1/7] lazy-pages: zero out pages not covered by the pagemap

[Mike Rapoport]

If a page was not marked "present" at the dump time it will not be covered
by the pagemap and it will remain unmapped in the restored process. We
should uffdio_zero such pages and let kernel mm to take over.

Signed-off-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
---
 criu/uffd.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/criu/uffd.c b/criu/uffd.c
index 000de14..f78c512 100644
--- a/criu/uffd.c
+++ b/criu/uffd.c
@@ -588,10 +588,7 @@ static int uffd_seek_or_zero_pages(struct lazy_pages_info *lpi, __u64 address,
 	lpi->pr.reset(&lpi->pr);
 
 	ret = lpi->pr.seek_pagemap(&lpi->pr, address, false);
-	if (!ret)
-		return 0;
-
-	if (pagemap_zero(lpi->pr.pe))
+	if (!ret || pagemap_zero(lpi->pr.pe))
 		return uffd_zero(lpi, address, nr);
 
 	lpi->pr.skip_pages(&lpi->pr, address - lpi->pr.pe->vaddr);
-- 
1.9.1