From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756009AbbJGV3H (ORCPT ); Wed, 7 Oct 2015 17:29:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55949 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754754AbbJGV3E (ORCPT ); Wed, 7 Oct 2015 17:29:04 -0400 From: Laura Abbott To: Srinivas Kandagatla , Vlastimil Babka , Bjorn Andersson Cc: Laura Abbott , Santosh Shilimkar , Russell King , Kevin Hilman , Arnd Bergman , Stephen Boyd , Andy Gross , Mel Gorman , Steven Rostedt , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Laura Abbott Subject: [PATCHv4] mm: Don't offset memmap for flatmem Date: Wed, 7 Oct 2015 14:28:55 -0700 Message-Id: <1444253335-5811-1-git-send-email-labbott@fedoraproject.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Laura Abbott 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 Signed-off-by: Laura Abbott Reported-by: Srinivas Kandagatla Tested-by: Srinivas Kandagatla Acked-by: Vlastimil Babka Tested-by: Bjorn Andersson --- I was reminded at Linaro Connect that I never followed up on this patch. v3 (http://marc.info/?l=linux-mm&m=142629173021316&w=2) was dropped due to crashing (https://lkml.org/lkml/2015/3/20/546) The fundamentals of the patch were fine, the VM_BUG_ON I added turned out to be incorrect. It was supposed to be a sanity check but it didn't actually hold true in all cases (or even most cases...) v4 just drops the sanity check. I verified that the offset is working on both ARM, x86, and i386 QEMU with the config provided by Steven Rostedt. Since this was minor diff from the previous patch, I kept all the previous Acked-by/Tested-by. --- mm/page_alloc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 40e2942..9e5ba5e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4953,6 +4953,8 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) { + unsigned long __maybe_unused offset = 0; + /* Skip empty nodes */ if (!pgdat->node_spanned_pages) return; @@ -4969,6 +4971,7 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) * for the buddy allocator to function correctly. */ start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1); + offset = pgdat->node_start_pfn - start; end = pgdat_end_pfn(pgdat); end = ALIGN(end, MAX_ORDER_NR_PAGES); size = (end - start) * sizeof(struct page); @@ -4976,7 +4979,7 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) if (!map) map = memblock_virt_alloc_node_nopanic(size, pgdat->node_id); - pgdat->node_mem_map = map + (pgdat->node_start_pfn - start); + pgdat->node_mem_map = map + offset; } #ifndef CONFIG_NEED_MULTIPLE_NODES /* @@ -4984,9 +4987,9 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) */ if (pgdat == NODE_DATA(0)) { mem_map = NODE_DATA(0)->node_mem_map; -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP +#if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM) if (page_to_pfn(mem_map) != pgdat->node_start_pfn) - mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET); + mem_map -= offset; #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ } #endif -- 2.4.3 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f48.google.com (mail-pa0-f48.google.com [209.85.220.48]) by kanga.kvack.org (Postfix) with ESMTP id A31036B0038 for ; Wed, 7 Oct 2015 17:29:05 -0400 (EDT) Received: by padhy16 with SMTP id hy16so32174909pad.1 for ; Wed, 07 Oct 2015 14:29:05 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id z5si60701879pbt.98.2015.10.07.14.29.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 07 Oct 2015 14:29:04 -0700 (PDT) From: Laura Abbott Subject: [PATCHv4] mm: Don't offset memmap for flatmem Date: Wed, 7 Oct 2015 14:28:55 -0700 Message-Id: <1444253335-5811-1-git-send-email-labbott@fedoraproject.org> Sender: owner-linux-mm@kvack.org List-ID: To: Srinivas Kandagatla , Vlastimil Babka , Bjorn Andersson Cc: Laura Abbott , Santosh Shilimkar , Russell King , Kevin Hilman , Arnd Bergman , Stephen Boyd , Andy Gross , Mel Gorman , Steven Rostedt , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Laura Abbott From: Laura Abbott 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 Signed-off-by: Laura Abbott Reported-by: Srinivas Kandagatla Tested-by: Srinivas Kandagatla Acked-by: Vlastimil Babka Tested-by: Bjorn Andersson --- I was reminded at Linaro Connect that I never followed up on this patch. v3 (http://marc.info/?l=linux-mm&m=142629173021316&w=2) was dropped due to crashing (https://lkml.org/lkml/2015/3/20/546) The fundamentals of the patch were fine, the VM_BUG_ON I added turned out to be incorrect. It was supposed to be a sanity check but it didn't actually hold true in all cases (or even most cases...) v4 just drops the sanity check. I verified that the offset is working on both ARM, x86, and i386 QEMU with the config provided by Steven Rostedt. Since this was minor diff from the previous patch, I kept all the previous Acked-by/Tested-by. --- mm/page_alloc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 40e2942..9e5ba5e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4953,6 +4953,8 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) { + unsigned long __maybe_unused offset = 0; + /* Skip empty nodes */ if (!pgdat->node_spanned_pages) return; @@ -4969,6 +4971,7 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) * for the buddy allocator to function correctly. */ start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1); + offset = pgdat->node_start_pfn - start; end = pgdat_end_pfn(pgdat); end = ALIGN(end, MAX_ORDER_NR_PAGES); size = (end - start) * sizeof(struct page); @@ -4976,7 +4979,7 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) if (!map) map = memblock_virt_alloc_node_nopanic(size, pgdat->node_id); - pgdat->node_mem_map = map + (pgdat->node_start_pfn - start); + pgdat->node_mem_map = map + offset; } #ifndef CONFIG_NEED_MULTIPLE_NODES /* @@ -4984,9 +4987,9 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) */ if (pgdat == NODE_DATA(0)) { mem_map = NODE_DATA(0)->node_mem_map; -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP +#if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM) if (page_to_pfn(mem_map) != pgdat->node_start_pfn) - mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET); + mem_map -= offset; #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ } #endif -- 2.4.3 -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: labbott@fedoraproject.org (Laura Abbott) Date: Wed, 7 Oct 2015 14:28:55 -0700 Subject: [PATCHv4] mm: Don't offset memmap for flatmem Message-ID: <1444253335-5811-1-git-send-email-labbott@fedoraproject.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Laura Abbott 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 Signed-off-by: Laura Abbott Reported-by: Srinivas Kandagatla Tested-by: Srinivas Kandagatla Acked-by: Vlastimil Babka Tested-by: Bjorn Andersson --- I was reminded at Linaro Connect that I never followed up on this patch. v3 (http://marc.info/?l=linux-mm&m=142629173021316&w=2) was dropped due to crashing (https://lkml.org/lkml/2015/3/20/546) The fundamentals of the patch were fine, the VM_BUG_ON I added turned out to be incorrect. It was supposed to be a sanity check but it didn't actually hold true in all cases (or even most cases...) v4 just drops the sanity check. I verified that the offset is working on both ARM, x86, and i386 QEMU with the config provided by Steven Rostedt. Since this was minor diff from the previous patch, I kept all the previous Acked-by/Tested-by. --- mm/page_alloc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 40e2942..9e5ba5e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4953,6 +4953,8 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) { + unsigned long __maybe_unused offset = 0; + /* Skip empty nodes */ if (!pgdat->node_spanned_pages) return; @@ -4969,6 +4971,7 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) * for the buddy allocator to function correctly. */ start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1); + offset = pgdat->node_start_pfn - start; end = pgdat_end_pfn(pgdat); end = ALIGN(end, MAX_ORDER_NR_PAGES); size = (end - start) * sizeof(struct page); @@ -4976,7 +4979,7 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) if (!map) map = memblock_virt_alloc_node_nopanic(size, pgdat->node_id); - pgdat->node_mem_map = map + (pgdat->node_start_pfn - start); + pgdat->node_mem_map = map + offset; } #ifndef CONFIG_NEED_MULTIPLE_NODES /* @@ -4984,9 +4987,9 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) */ if (pgdat == NODE_DATA(0)) { mem_map = NODE_DATA(0)->node_mem_map; -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP +#if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM) if (page_to_pfn(mem_map) != pgdat->node_start_pfn) - mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET); + mem_map -= offset; #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ } #endif -- 2.4.3