From 3d680bdf60a5bade3e8cbd049927e7f8b1d3fe97 Mon Sep 17 00:00:00 2001 From: Qian Cai Date: Thu, 30 Jan 2020 22:15:01 -0800 Subject: mm/page_isolation: fix potential warning from user It makes sense to call the WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE) from start_isolate_page_range(), but should avoid triggering it from userspace, i.e, from is_mem_section_removable() because it could crash the system by a non-root user if warn_on_panic is set. While at it, simplify the code a bit by removing an unnecessary jump label. Link: http://lkml.kernel.org/r/20200120163915.1469-1-cai@lca.pw Signed-off-by: Qian Cai Suggested-by: Michal Hocko Acked-by: Michal Hocko Reviewed-by: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_isolation.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'mm/page_isolation.c') diff --git a/mm/page_isolation.c b/mm/page_isolation.c index e70586523ca3..a9fd7c740c23 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -54,14 +54,18 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_ out: spin_unlock_irqrestore(&zone->lock, flags); - if (!ret) + if (!ret) { drain_all_pages(zone); - else if ((isol_flags & REPORT_FAILURE) && unmovable) - /* - * printk() with zone->lock held will guarantee to trigger a - * lockdep splat, so defer it here. - */ - dump_page(unmovable, "unmovable page"); + } else { + WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE); + + if ((isol_flags & REPORT_FAILURE) && unmovable) + /* + * printk() with zone->lock held will likely trigger a + * lockdep splat, so defer it here. + */ + dump_page(unmovable, "unmovable page"); + } return ret; } -- cgit v1.2.3