Re: [PATCH 1/2] mm: page_isolation: check pfn validity before access

From: Yasuaki Ishimatsu
Date: Tue Nov 11 2014 - 21:03:08 EST


(2014/11/06 17:08), Weijie Yang wrote:
In the undo path of start_isolate_page_range(), we need to check
the pfn validity before access its page, or it will trigger an
addressing exception if there is hole in the zone.

Signed-off-by: Weijie Yang <weijie.yang@xxxxxxxxxxx>
---

Looks good to me.

Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>

Thanks,
Yasuaki Ishimatsu

mm/page_isolation.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index d1473b2..3ddc8b3 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -137,8 +137,11 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
undo:
for (pfn = start_pfn;
pfn < undo_pfn;
- pfn += pageblock_nr_pages)
- unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
+ pfn += pageblock_nr_pages) {
+ page = __first_valid_page(pfn, pageblock_nr_pages);
+ if (page)
+ unset_migratetype_isolate(page, migratetype);
+ }

return -EBUSY;
}



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