[PATCH] mm: fix invalid use of pfn_valid_within in test_pages_in_a_zone
STALE4314d
From: James Custer <hidden>
Date: 2014-12-09 19:35:01
Also in:
lkml
Subsystem:
memory hot(un)plug, memory management, the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Andrew Morton, Linus Torvalds
Offlining memory by 'echo 0 > /sys/devices/system/memory/memory#/online' or reading valid_zones 'cat /sys/devices/system/memory/memory#/valid_zones' causes BUG: unable to handle kernel paging request due to invalid use of pfn_valid_within. This is due to a bug in test_pages_in_a_zone. In order to use pfn_valid_within within a MAX_ORDER_NR_PAGES block of pages, a valid pfn within the block must first be found. There only needs to be one valid pfn found in test_pages_in_a_zone in the first place. So the fix is to replace pfn_valid_within with pfn_valid such that the first valid pfn within the pageblock is found (if it exists). This works independently of CONFIG_HOLES_IN_ZONE. Signed-off-by: James Custer <redacted> --- mm/memory_hotplug.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1bf4807..304c187 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c@@ -1331,7 +1331,7 @@ int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) } /* - * Confirm all pages in a range [start, end) is belongs to the same zone. + * Confirm all pages in a range [start, end) belong to the same zone. */ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) {
@@ -1342,10 +1342,11 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) for (pfn = start_pfn; pfn < end_pfn; pfn += MAX_ORDER_NR_PAGES) { - i = 0; - /* This is just a CONFIG_HOLES_IN_ZONE check.*/ - while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) - i++; + /* Find the first valid pfn in this pageblock */ + for (i = 0; i < MAX_ORDER_NR_PAGES; i++) { + if (pfn_valid(pfn + i)) + break; + } if (i == MAX_ORDER_NR_PAGES) continue; page = pfn_to_page(pfn + i);
--
1.8.2.1
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