hugetlb: fix handling of parse errors in sysfs

When parsing changes to the huge page pool sizes made from userspace via
the sysfs interface, bogus input values are being covered up by
nr_hugepages_store_common and nr_overcommit_hugepages_store returning 0
when strict_strtoul returns an error.  This can cause an infinite loop in
the nr_hugepages_store code.  This patch changes the return value for
these functions to -EINVAL when strict_strtoul returns an error.

Signed-off-by: Eric B Munson <[email protected]>
Reported-by: CAI Qian <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Eric B Munson <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Nishanth Aravamudan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 2 insertions, 4 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ce8e5bb6f031..bb0b7c128015 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1375,10 +1375,8 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
 	NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
 
 	err = strict_strtoul(buf, 10, &count);
-	if (err) {
-		err = 0;		/* This seems wrong */
+	if (err)
 		goto out;
-	}
 
 	h = kobj_to_hstate(kobj, &nid);
 	if (h->order >= MAX_ORDER) {
@@ -1469,7 +1467,7 @@ static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
 
 	err = strict_strtoul(buf, 10, &input);
 	if (err)
-		return 0;
+		return err;
 
 	spin_lock(&hugetlb_lock);
 	h->nr_overcommit_huge_pages = input;