| From c2cc499c5bcf9040a738f49e8051b42078205748 Mon Sep 17 00:00:00 2001 |
| From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> |
| Date: Fri, 24 May 2013 15:55:18 -0700 |
| Subject: mm compaction: fix of improper cache flush in migration code |
| |
| From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> |
| |
| commit c2cc499c5bcf9040a738f49e8051b42078205748 upstream. |
| |
| 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@imgtec.com> |
| Cc: Leonid Yegoshin <yegoshin@mips.com> |
| Acked-by: Rik van Riel <riel@redhat.com> |
| Cc: Michal Hocko <mhocko@suse.cz> |
| Acked-by: Mel Gorman <mgorman@suse.de> |
| Cc: Ralf Baechle <ralf@linux-mips.org> |
| Cc: Russell King <rmk@arm.linux.org.uk> |
| Cc: David Miller <davem@davemloft.net> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/migrate.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/mm/migrate.c |
| +++ b/mm/migrate.c |
| @@ -145,7 +145,7 @@ static int remove_migration_pte(struct p |
| if (PageHuge(new)) |
| pte = pte_mkhuge(pte); |
| #endif |
| - flush_cache_page(vma, addr, pte_pfn(pte)); |
| + flush_dcache_page(new); |
| set_pte_at(mm, addr, ptep, pte); |
| |
| if (PageHuge(new)) { |
