From: Weijie Yang <[email protected]> Subject: mm: page_isolation: check pfn validity before access
In the undo path of start_isolate_page_range(), we need to check the pfn validity before accessing its page, or it will trigger an addressing exception if there is hole in the zone. This issue is found by code-review not a test-trigger. In "CONFIG_HOLES_IN_ZONE" environment, there is a certain chance that it would casue an addressing exception when start_isolate_page_range() fails, this could affect CMA, hugepage and memory-hotplug function. Signed-off-by: Weijie Yang <[email protected]> Acked-by: Michal Nazarewicz <[email protected]> Reviewed-by: Yasuaki Ishimatsu <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Michal Hocko <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- mm/page_isolation.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff -puN mm/page_isolation.c~mm-page_isolation-check-pfn-validity-before-access mm/page_isolation.c --- a/mm/page_isolation.c~mm-page_isolation-check-pfn-validity-before-access +++ a/mm/page_isolation.c @@ -176,8 +176,11 @@ int start_isolate_page_range(unsigned lo undo: for (pfn = start_pfn; pfn < undo_pfn; - pfn += pageblock_nr_pages) - unset_migratetype_isolate(pfn_to_page(pfn), migratetype); + pfn += pageblock_nr_pages) { + page = __first_valid_page(pfn, pageblock_nr_pages); + if (page) + unset_migratetype_isolate(page, migratetype); + } return -EBUSY; } _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
