From: Michal Hocko <mhocko@xxxxxxxx> Subject: mm, page_alloc: fail has_unmovable_pages when seeing reserved pages Reserved pages should be completely ignored by the core mm because they have a special meaning for their owners. has_unmovable_pages doesn't check those so we rely on other tests (reference count, or PageLRU) to fail on such pages. Althought this happens to work it is safer to simply check for those explicitly and do not rely on the owner of the page to abuse those fields for special purposes. Please note that this is more of a further fortification of the code rahter than a fix of an existing issue. Link: http://lkml.kernel.org/r/20171013120756.jeopthigbmm3c7bl@xxxxxxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Igor Mammedov <imammedo@xxxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx> Cc: Yasuaki Ishimatsu <yasu.isimatu@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 3 +++ 1 file changed, 3 insertions(+) diff -puN mm/page_alloc.c~mm-page_alloc-fail-has_unmovable_pages-when-seeing-reserved-pages mm/page_alloc.c --- a/mm/page_alloc.c~mm-page_alloc-fail-has_unmovable_pages-when-seeing-reserved-pages +++ a/mm/page_alloc.c @@ -7383,6 +7383,9 @@ bool has_unmovable_pages(struct zone *zo page = pfn_to_page(check); + if (PageReserved(page)) + return true; + /* * Hugepages are not in LRU lists, but they're movable. * We need not scan over tail pages bacause we don't _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
