Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762358AbaGRN44 (ORCPT ); Fri, 18 Jul 2014 09:56:56 -0400 Received: from bband-dyn38.178-41-141.t-com.sk ([178.41.141.38]:17453 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761325AbaGRNJm (ORCPT ); Fri, 18 Jul 2014 09:09:42 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Michal Nazarewicz , Mel Gorman , David Rientjes , Marek Szyprowski , Catalin Marinas , Andrew Morton , Linus Torvalds , Jiri Slaby Subject: [PATCH 3.12 119/170] mm: page_alloc: fix CMA area initialisation when pageblock > MAX_ORDER Date: Fri, 18 Jul 2014 14:12:04 +0200 Message-Id: <842d2aecf2d282bfd42372a1d8f9b6ce2701b637.1405685481.git.jslaby@suse.cz> X-Mailer: git-send-email 2.0.0 In-Reply-To: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> References: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michal Nazarewicz 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit dc78327c0ea7da5186d8cbc1647bd6088c5c9fa5 upstream. With a kernel configured with ARM64_64K_PAGES && !TRANSPARENT_HUGEPAGE, the following is triggered at early boot: SMP: Total of 8 processors activated. devtmpfs: initialized Unable to handle kernel NULL pointer dereference at virtual address 00000008 pgd = fffffe0000050000 [00000008] *pgd=00000043fba00003, *pmd=00000043fba00003, *pte=00e0000078010407 Internal error: Oops: 96000006 [#1] SMP Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.15.0-rc864k+ #44 task: fffffe03bc040000 ti: fffffe03bc080000 task.ti: fffffe03bc080000 PC is at __list_add+0x10/0xd4 LR is at free_one_page+0x270/0x638 ... Call trace: __list_add+0x10/0xd4 free_one_page+0x26c/0x638 __free_pages_ok.part.52+0x84/0xbc __free_pages+0x74/0xbc init_cma_reserved_pageblock+0xe8/0x104 cma_init_reserved_areas+0x190/0x1e4 do_one_initcall+0xc4/0x154 kernel_init_freeable+0x204/0x2a8 kernel_init+0xc/0xd4 This happens because init_cma_reserved_pageblock() calls __free_one_page() with pageblock_order as page order but it is bigger than MAX_ORDER. This in turn causes accesses past zone->free_list[]. Fix the problem by changing init_cma_reserved_pageblock() such that it splits pageblock into individual MAX_ORDER pages if pageblock is bigger than a MAX_ORDER page. In cases where !CONFIG_HUGETLB_PAGE_SIZE_VARIABLE, which is all architectures expect for ia64, powerpc and tile at the moment, the “pageblock_order > MAX_ORDER” condition will be optimised out since both sides of the operator are constants. In cases where pageblock size is variable, the performance degradation should not be significant anyway since init_cma_reserved_pageblock() is called only at boot time at most MAX_CMA_AREAS times which by default is eight. Signed-off-by: Michal Nazarewicz Reported-by: Mark Salter Tested-by: Mark Salter Tested-by: Christopher Covington Cc: Mel Gorman Cc: David Rientjes Cc: Marek Szyprowski Cc: Catalin Marinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- mm/page_alloc.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 83aaa49bcba7..6e0a9cf8d02a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -785,9 +785,21 @@ void __init init_cma_reserved_pageblock(struct page *page) set_page_count(p, 0); } while (++p, --i); - set_page_refcounted(page); set_pageblock_migratetype(page, MIGRATE_CMA); - __free_pages(page, pageblock_order); + + if (pageblock_order >= MAX_ORDER) { + i = pageblock_nr_pages; + p = page; + do { + set_page_refcounted(p); + __free_pages(p, MAX_ORDER - 1); + p += MAX_ORDER_NR_PAGES; + } while (i -= MAX_ORDER_NR_PAGES); + } else { + set_page_refcounted(page); + __free_pages(page, pageblock_order); + } + adjust_managed_page_count(page, pageblock_nr_pages); } #endif -- 2.0.0 -- 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/