Commit a70dcb96 authored Nov 06, 2008 by Gerald Schaefer Committed by Linus Torvalds Nov 06, 2008

memory hotplug: fix page_zone() calculation in test_pages_isolated()



My last bugfix here (adding zone->lock) introduced a new problem: Using
page_zone(pfn_to_page(pfn)) to get the zone after the for() loop is wrong.
 pfn will then be >= end_pfn, which may be in a different zone or not
present at all.  This may lead to an addressing exception in page_zone()
or spin_lock_irqsave().

Now I use __first_valid_page() again after the loop to find a valid page
for page_zone().

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: Nathan Fontenot <nfont@austin.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c87591b7

mm/page_isolation.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -130,10 +130,11 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
		if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
		break;
		}
		if (pfn < end_pfn)
		page = __first_valid_page(start_pfn, end_pfn - start_pfn);
		if ((pfn < end_pfn) \|\| !page)
		return -EBUSY;
		/* Check all pages are free or Marked as ISOLATED */
		zone = page_zone(pfn_to_page(pfn));
		zone = page_zone(page);
		spin_lock_irqsave(&zone->lock, flags);
		ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn);
		spin_unlock_irqrestore(&zone->lock, flags);

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