From bd02cc01d342b43618c86e25552150f7a7e09080 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 23 Sep 2019 15:36:05 -0700 Subject: mm/memory_hotplug: make sure the pfn is aligned to the order when onlining Commit a9cd410a3d29 ("mm/page_alloc.c: memory hotplug: free pages as higher order") assumed that any PFN we get via memory resources is aligned to to MAX_ORDER - 1, I am not convinced that is always true. Let's play safe, check the alignment and fallback to single pages. akpm: warn in this situation so we get to find out if and why this ever occurs. [akpm@linux-foundation.org: add WARN_ON_ONCE()] Link: http://lkml.kernel.org/r/20190814154109.3448-5-david@redhat.com Signed-off-by: David Hildenbrand Cc: Arun KS Cc: Oscar Salvador Cc: Michal Hocko Cc: Pavel Tatashin Cc: Dan Williams Cc: Bjorn Helgaas Cc: Borislav Petkov Cc: Dave Hansen Cc: Ingo Molnar Cc: Nadav Amit Cc: Wei Yang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b5ad646df86b..aa54e15ea830 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -646,6 +646,9 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, */ for (pfn = start_pfn; pfn < end_pfn; pfn += 1ul << order) { order = min(MAX_ORDER - 1, get_order(PFN_PHYS(end_pfn - pfn))); + /* __free_pages_core() wants pfns to be aligned to the order */ + if (WARN_ON_ONCE(!IS_ALIGNED(pfn, 1ul << order))) + order = 0; (*online_page_callback)(pfn_to_page(pfn), order); } -- cgit v1.2.3-59-g8ed1b