[08/67] mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()

Commit Message

Andrew Morton Feb. 4, 2020, 1:34 a.m. UTC

From: David Hildenbrand <[e-mail]>
Subject: mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()

Let's poison the pages similar to when adding new memory in
sparse_add_section().  Also call remove_pfn_range_from_zone() from
memunmap_pages(), so we can poison the memmap from there as well.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: David Hildenbrand <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: "Matthew Wilcox (Oracle)" <[e-mail]>
Cc: "Aneesh Kumar K.V" <[e-mail]>
Cc: Pavel Tatashin <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Dan Williams <[e-mail]>
Cc: Logan Gunthorpe <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Pankaj Gupta <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/memory_hotplug.c |    3 +++
 mm/memremap.c       |    2 ++
 2 files changed, 5 insertions(+)

Patch

--- a/mm/memory_hotplug.c~mm-memory_hotplug-poison-memmap-in-remove_pfn_range_from_zone
+++ a/mm/memory_hotplug.c
@@ -490,6 +490,9 @@  void __ref remove_pfn_range_from_zone(st
 	struct pglist_data *pgdat = zone->zone_pgdat;
 	unsigned long flags;
 
+	/* Poison struct pages because they are now uninitialized again. */
+	page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages);
+
 #ifdef CONFIG_ZONE_DEVICE
 	/*
 	 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
--- a/mm/memremap.c~mm-memory_hotplug-poison-memmap-in-remove_pfn_range_from_zone
+++ a/mm/memremap.c
@@ -120,6 +120,8 @@  void memunmap_pages(struct dev_pagemap *
 	nid = page_to_nid(first_page);
 
 	mem_hotplug_begin();
+	remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(res->start),
+				   PHYS_PFN(resource_size(res)));
 	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
 		__remove_pages(PHYS_PFN(res->start),
 			       PHYS_PFN(resource_size(res)), NULL);