Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753345Ab3EIAT3 (ORCPT ); Wed, 8 May 2013 20:19:29 -0400 Received: from multi.imgtec.com ([194.200.65.239]:61045 "EHLO multi.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752183Ab3EIAT1 (ORCPT ); Wed, 8 May 2013 20:19:27 -0400 Subject: [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code. To: , , , , From: Leonid Yegoshin CC: , Date: Wed, 8 May 2013 17:18:21 -0700 Message-ID: <20130509001821.15951.98705.stgit@linux-yegoshin> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-SEF-Processed: 7_3_0_01181__2013_05_09_01_19_24 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1669 Lines: 45 Page 'new' during MIGRATION can't be flushed by flush_cache_page(). Using flush_cache_page(vma, addr, pfn) is justified only if 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, kernel has a different page virtual address and dirtied it. Replace it with flush_dcache_page(new) which is a proper usage. 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. Author: Leonid Yegoshin Signed-off-by: Leonid Yegoshin --- mm/migrate.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 2fd8b4a..4c6250a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -165,7 +165,7 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, 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)) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/