From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f180.google.com (mail-wi0-f180.google.com [209.85.212.180]) by kanga.kvack.org (Postfix) with ESMTP id 32F846B006E for ; Wed, 18 Mar 2015 08:15:44 -0400 (EDT) Received: by wibdy8 with SMTP id dy8so88532093wib.0 for ; Wed, 18 Mar 2015 05:15:43 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id d2si3253509wib.111.2015.03.18.05.15.42 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 18 Mar 2015 05:15:42 -0700 (PDT) Message-ID: <55096C6B.4010603@suse.cz> Date: Wed, 18 Mar 2015 13:15:39 +0100 From: Vlastimil Babka MIME-Version: 1.0 Subject: Re: [PATCHv3] mm: Don't offset memmap for flatmem References: <1426291715-16242-1-git-send-email-lauraa@codeaurora.org> In-Reply-To: <1426291715-16242-1-git-send-email-lauraa@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Laura Abbott , Srinivas Kandagatla , linux-arm-kernel@lists.infradead.org, Russell King - ARM Linux , ssantosh@kernel.org, Andrew Morton Cc: Kevin Hilman , Arnd Bergman , Stephen Boyd , linux-mm@kvack.org, Kumar Gala , Mel Gorman On 03/14/2015 01:08 AM, Laura Abbott wrote: > Srinivas Kandagatla reported bad page messages when trying to > remove the bottom 2MB on an ARM based IFC6410 board > > BUG: Bad page state in process swapper pfn:fffa8 > page:ef7fb500 count:0 mapcount:0 mapping: (null) index:0x0 > flags: 0x96640253(locked|error|dirty|active|arch_1|reclaim|mlocked) > page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set > bad because of flags: > flags: 0x200041(locked|active|mlocked) > Modules linked in: > CPU: 0 PID: 0 Comm: swapper Not tainted 3.19.0-rc3-00007-g412f9ba-dirty #816 > Hardware name: Qualcomm (Flattened Device Tree) > [] (unwind_backtrace) from [] (show_stack+0x20/0x24) > [] (show_stack) from [] (dump_stack+0x80/0x9c) > [] (dump_stack) from [] (bad_page+0xc8/0x128) > [] (bad_page) from [] (free_pages_prepare+0x168/0x1e0) > [] (free_pages_prepare) from [] (free_hot_cold_page+0x3c/0x174) > [] (free_hot_cold_page) from [] (__free_pages+0x54/0x58) > [] (__free_pages) from [] (free_highmem_page+0x38/0x88) > [] (free_highmem_page) from [] (mem_init+0x240/0x430) > [] (mem_init) from [] (start_kernel+0x1e4/0x3c8) > [] (start_kernel) from [<80208074>] (0x80208074) > Disabling lock debugging due to kernel taint > > Removing the lower 2MB made the start of the lowmem zone to no longer > be page block aligned. IFC6410 uses CONFIG_FLATMEM where > alloc_node_mem_map allocates memory for the mem_map. alloc_node_mem_map > will offset for unaligned nodes with the assumption the pfn/page > translation functions will account for the offset. The functions for > CONFIG_FLATMEM do not offset however, resulting in overrunning > the memmap array. Just use the allocated memmap without any offset > when running with CONFIG_FLATMEM to avoid the overrun. > > Signed-off-by: Laura Abbott > Reported-by: Srinivas Kandagatla Acked-by: Vlastimil Babka Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org