Messages in this thread Patch in this message | | | Subject | [PATCH] memory hotplug: fix page_zone() calculation in test_pages_isolated() | From | Gerald Schaefer <> | Date | Mon, 27 Oct 2008 18:19:09 +0100 |
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From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
My last bugfix here (adding zone->lock) introduced a new problem: Using pfn_to_page(pfn) to get the zone after the for() loop is wrong. pfn then points to the first pfn after 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().
Using the last valid page that was found inside the for() loop, instead of pfn_to_page(), should fix this.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
--- mm/page_isolation.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
Index: linux-2.6/mm/page_isolation.c =================================================================== --- linux-2.6.orig/mm/page_isolation.c +++ linux-2.6/mm/page_isolation.c @@ -115,7 +115,7 @@ __test_page_isolated_in_pageblock(unsign int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn, flags; - struct page *page; + struct page *page = NULL; struct zone *zone; int ret; @@ -130,10 +130,10 @@ int test_pages_isolated(unsigned long st if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) break; } - if (pfn < end_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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