Commit de4c175c authored by zhong jiang's avatar zhong jiang Committed by Greg Kroah-Hartman

mm/memory_hotplug.c: fix overflow in test_pages_in_a_zone()

[ Upstream commit d6d8c8a4 ]

When mainline introduced commit a96dfddb ("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.

[toshi.kani@hpe.com: remove assumption that end_pfn is aligned by MAX_ORDER_NR_PAGES]
Fixes: a96dfddb ("base/memory, hotplug: fix a kernel oops in show_valid_zones()")
Link: http://lkml.kernel.org/r/1486467299-22648-1-git-send-email-zhongjiang@huawei.comSigned-off-by: 's avatarzhong jiang <zhongjiang@huawei.com>
Signed-off-by: 's avatarToshi Kani <toshi.kani@hpe.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: 's avatarSasha Levin <sashal@kernel.org>
parent 698f6acd
......@@ -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;
......
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