From: David Rientjes Date: Fri, 26 Oct 2018 22:09:24 +0000 (-0700) Subject: mm/page_alloc.c: initialize num_movable in move_freepages() X-Git-Tag: v4.20-rc1~92^2~24 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=4a222127f3631e6cdde228e3bb6b599f52b96d14;p=people%2Froyger%2Flinux.git mm/page_alloc.c: initialize num_movable in move_freepages() If move_freepages_block() returns 0 because !zone_spans_pfn(), *num_movable can hold the value from the stack because it does not get initialized in move_freepages(). Move the initialization to move_freepages_block() to guarantee the value actually makes sense. This currently doesn't affect its only caller where num_movable != NULL, so no bug fix, but just more robust. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1810051355490.212229@chino.kir.corp.google.com Signed-off-by: David Rientjes Reviewed-by: Andrew Morton Acked-by: Vlastimil Babka Cc: Greg Thelen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d73ff2188d72..bdb7eb25acf8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2021,10 +2021,6 @@ static int move_freepages(struct zone *zone, pfn_valid(page_to_pfn(end_page)) && page_zone(start_page) != page_zone(end_page)); #endif - - if (num_movable) - *num_movable = 0; - for (page = start_page; page <= end_page;) { if (!pfn_valid_within(page_to_pfn(page))) { page++; @@ -2064,6 +2060,9 @@ int move_freepages_block(struct zone *zone, struct page *page, unsigned long start_pfn, end_pfn; struct page *start_page, *end_page; + if (num_movable) + *num_movable = 0; + start_pfn = page_to_pfn(page); start_pfn = start_pfn & ~(pageblock_nr_pages-1); start_page = pfn_to_page(start_pfn);