[merged] mm-compaction-fix-of-improper-cache-flush-in-migration-code.patch removed from -mm tree

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Subject: [merged] mm-compaction-fix-of-improper-cache-flush-in-migration-code.patch removed from -mm tree
To: Leonid.Yegoshin@xxxxxxxxxx,davem@xxxxxxxxxxxxx,mgorman@xxxxxxx,mhocko@xxxxxxx,ralf@xxxxxxxxxxxxxx,riel@xxxxxxxxxx,rmk@xxxxxxxxxxxxxxxx,stable@xxxxxxxxxxxxxxx,yegoshin@xxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 28 May 2013 12:36:53 -0700


The patch titled
     Subject: mm compaction: fix of improper cache flush in migration code
has been removed from the -mm tree.  Its filename was
     mm-compaction-fix-of-improper-cache-flush-in-migration-code.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
Subject: mm compaction: fix of improper cache flush in migration code

Page 'new' during MIGRATION can't be flushed with flush_cache_page(). 
Using flush_cache_page(vma, addr, pfn) is justified only if the page is
already placed in process page table, and that is done right after
flush_cache_page().  But without it the arch function has no knowledge of
process PTE and does nothing.

Besides that, flush_cache_page() flushes an application cache page, but
the kernel has a different page virtual address and dirtied it.

Replace it with flush_dcache_page(new) which is the proper usage.

The old page is flushed in try_to_unmap_one() before migration.

This bug takes place in Sead3 board with M14Kc MIPS CPU without cache
aliasing (but Harvard arch - separate I and D cache) in tight memory
environment (128MB) each 1-3days on SOAK test.  It fails in cc1 during
kernel build (SIGILL, SIGBUS, SIGSEG) if CONFIG_COMPACTION is switched ON.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
Cc: Leonid Yegoshin <yegoshin@xxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/migrate.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/migrate.c~mm-compaction-fix-of-improper-cache-flush-in-migration-code mm/migrate.c
--- a/mm/migrate.c~mm-compaction-fix-of-improper-cache-flush-in-migration-code
+++ a/mm/migrate.c
@@ -165,7 +165,7 @@ static int remove_migration_pte(struct p
 		pte = arch_make_huge_pte(pte, vma, new, 0);
 	}
 #endif
-	flush_cache_page(vma, addr, pte_pfn(pte));
+	flush_dcache_page(new);
 	set_pte_at(mm, addr, ptep, pte);
 
 	if (PageHuge(new)) {
_

Patches currently in -mm which might be from Leonid.Yegoshin@xxxxxxxxxx are


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