The patch titled Subject: mm, compaction: use free lists to quickly locate a migration target -fix has been added to the -mm tree. Its filename is mm-compaction-use-free-lists-to-quickly-locate-a-migration-target-fix.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-compaction-use-free-lists-to-quickly-locate-a-migration-target-fix.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-compaction-use-free-lists-to-quickly-locate-a-migration-target-fix.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Subject: mm, compaction: use free lists to quickly locate a migration target -fix Full compaction of a node passes in negative orders which can lead to array boundary issues. While it could be addressed in the control flow of the primary loop, it would be fragile so explicitly check for the condition. This is a fix for the mmotm patch broken-out/mm-compaction-use-free-lists-to-quickly-locate-a-migration-target.patch Link: http://lkml.kernel.org/r/20190109111344.GU31517@xxxxxxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Huang Ying <ying.huang@xxxxxxxxx> Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/compaction.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/mm/compaction.c~mm-compaction-use-free-lists-to-quickly-locate-a-migration-target-fix +++ a/mm/compaction.c @@ -1452,6 +1452,10 @@ static struct page *compaction_alloc(str struct compact_control *cc = (struct compact_control *)data; struct page *freepage; + /* Full compaction passes in a negative order */ + if (order <= 0) + return cc->free_pfn; + /* * Isolate free pages if necessary, and if we are not aborting due to * contention. _ Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are mm-compaction-shrink-compact_control.patch mm-compaction-rearrange-compact_control.patch mm-compaction-remove-last_migrated_pfn-from-compact_control.patch mm-compaction-remove-unnecessary-zone-parameter-in-some-instances.patch mm-compaction-rename-map_pages-to-split_map_pages.patch mm-compaction-skip-pageblocks-with-reserved-pages.patch mm-migrate-immediately-fail-migration-of-a-page-with-no-migration-handler.patch mm-compaction-always-finish-scanning-of-a-full-pageblock.patch mm-compaction-use-the-page-allocator-bulk-free-helper-for-lists-of-pages.patch mm-compaction-ignore-the-fragmentation-avoidance-boost-for-isolation-and-compaction.patch mm-compaction-use-free-lists-to-quickly-locate-a-migration-source.patch mm-compaction-keep-migration-source-private-to-a-single-compaction-instance.patch mm-compaction-use-free-lists-to-quickly-locate-a-migration-target.patch mm-compaction-use-free-lists-to-quickly-locate-a-migration-target-fix.patch mm-compaction-avoid-rescanning-the-same-pageblock-multiple-times.patch mm-compaction-finish-pageblock-scanning-on-contention.patch mm-compaction-finish-pageblock-scanning-on-contention-fix.patch mm-compaction-check-early-for-huge-pages-encountered-by-the-migration-scanner.patch mm-compaction-keep-cached-migration-pfns-synced-for-unusable-pageblocks.patch mm-compaction-rework-compact_should_abort-as-compact_check_resched.patch mm-compaction-do-not-consider-a-need-to-reschedule-as-contention.patch mm-compaction-reduce-unnecessary-skipping-of-migration-target-scanner.patch mm-compaction-round-robin-the-order-while-searching-the-free-lists-for-a-target.patch mm-compaction-round-robin-the-order-while-searching-the-free-lists-for-a-target-fix.patch mm-compaction-sample-pageblocks-for-free-pages.patch mm-compaction-be-selective-about-what-pageblocks-to-clear-skip-hints.patch mm-compaction-capture-a-page-under-direct-compaction.patch mm-compaction-do-not-direct-compact-remote-memory.patch