The patch titled
Subject: mm, compaction: fix crash in get_pfnblock_flags_mask() from isolate_freepages():
has been added to the -mm tree. Its filename is
compaction-wrap-calculating-first-and-last-pfn-of-pageblock-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/compaction-wrap-calculating-first-and-last-pfn-of-pageblock-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/compaction-wrap-calculating-first-and-last-pfn-of-pageblock-fix.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, compaction: fix crash in get_pfnblock_flags_mask() from isolate_freepages():
In isolate_freepages(), low_pfn was mistakenly initialized to
pageblock_start_pfn() instead of pageblock_end_pfn(), creating a possible
underflow, as described by Hugh:
There's a case when that "block_start_pfn -= pageblock_nr_pages" loop can
pass through 0 and end up trying to access a pageblock before the start of
the mem_map[].
Fixes: mmotm mm-compaction-wrap-calculating-first-and-last-pfn-of-pageblock.patch
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Reported-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/compaction.c~compaction-wrap-calculating-first-and-last-pfn-of-pageblock-fix mm/compaction.c
--- a/mm/compaction.c~compaction-wrap-calculating-first-and-last-pfn-of-pageblock-fix
+++ a/mm/compaction.c
@@ -932,7 +932,7 @@ static void isolate_freepages(struct com
block_start_pfn = pageblock_start_pfn(cc->free_pfn);
block_end_pfn = min(block_start_pfn + pageblock_nr_pages,
zone_end_pfn(zone));
- low_pfn = pageblock_start_pfn(cc->migrate_pfn);
+ low_pfn = pageblock_end_pfn(cc->migrate_pfn);
/*
* Isolate free pages until enough are available to migrate the
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-wake-kcompactd-before-kswapds-short-sleep.patch
mm-compaction-wrap-calculating-first-and-last-pfn-of-pageblock.patch
compaction-wrap-calculating-first-and-last-pfn-of-pageblock-fix.patch
mm-compaction-reduce-spurious-pcplist-drains.patch
mm-compaction-skip-blocks-where-isolation-fails-in-async-direct-compaction.patch
cpuset-use-static-key-better-and-convert-to-new-api.patch
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