4.9-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit d6d8c8a48291b929b2e039f220f0b62958cccfea ]
When mainline introduced commit a96dfddbcc04 ("base/memory, hotplug: fix
a kernel oops in show_valid_zones()"), it obtained the valid start and
end pfn from the given pfn range. The valid start pfn can fix the
actual issue, but it introduced another issue. The valid end pfn will
may exceed the given end_pfn.
Although the incorrect overflow will not result in actual problem at
present, but I think it need to be fixed.
[[email protected]: remove assumption that end_pfn is aligned by
MAX_ORDER_NR_PAGES]
Fixes: a96dfddbcc04 ("base/memory, hotplug: fix a kernel oops in
show_valid_zones()")
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: zhong jiang <[email protected]>
Signed-off-by: Toshi Kani <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
mm/memory_hotplug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index c9f715b2917f..0f962cc3f1bf 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1508,7 +1508,7 @@ int test_pages_in_a_zone(unsigned long start_pfn,
unsigned long end_pfn,
while ((i < MAX_ORDER_NR_PAGES) &&
!pfn_valid_within(pfn + i))
i++;
- if (i == MAX_ORDER_NR_PAGES)
+ if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
continue;
page = pfn_to_page(pfn + i);
if (zone && page_zone(page) != zone)
@@ -1522,7 +1522,7 @@ int test_pages_in_a_zone(unsigned long start_pfn,
unsigned long end_pfn,
if (zone) {
*valid_start = start;
- *valid_end = end;
+ *valid_end = min(end, end_pfn);
return 1;
} else {
return 0;
--
2.17.1
