From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id E96B34405B1 for ; Wed, 15 Feb 2017 15:58:46 -0500 (EST) Received: by mail-wr0-f199.google.com with SMTP id z61so7072489wrc.6 for ; Wed, 15 Feb 2017 12:58:46 -0800 (PST) Received: from mail-wr0-x244.google.com (mail-wr0-x244.google.com. [2a00:1450:400c:c0c::244]) by mx.google.com with ESMTPS id 43si6477327wrk.228.2017.02.15.12.58.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 Feb 2017 12:58:45 -0800 (PST) Received: by mail-wr0-x244.google.com with SMTP id k90so32522511wrc.3 for ; Wed, 15 Feb 2017 12:58:45 -0800 (PST) From: Nicolai Stange Subject: [RFC 1/3] sparse-vmemmap: let vmemmap_populate_basepages() cover the whole range Date: Wed, 15 Feb 2017 21:58:24 +0100 Message-Id: <20170215205826.13356-2-nicstange@gmail.com> In-Reply-To: <20170215205826.13356-1-nicstange@gmail.com> References: <20170215205826.13356-1-nicstange@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams Cc: Andrew Morton , linux-mm@kvack.org, Nicolai Stange vmemmap_populate_basepages() takes two memory addresses, start and end, and attempts to populate the page range covering it. Due to the way this is done, namely by means of a for (addr = start; addr < end; addr += PAGE_SIZE) { ... } loop, this misses the last necessary page in case of start % PAGE_SIZE > end % PAGE_SIZE. On x86, Kasan's initizalization in arch/x86/mm/kasan_init_64.c (ab)uses the arch-provided vmemmap_populate() for shadow memory population. The start and end addresses passed aren't necessarily page aligned. With commit 7b79d10a2d64 ("mm: convert kmalloc_section_memmap() to populate_section_memmap()"), the x86 specific vmemmap_populate() sometimes uses the aforementioned vmemmap_populate_basepages(). This results in non-populated shadow memory: BUG: unable to handle kernel paging request at ffffed0017b4d000 IP: memset_erms+0x9/0x10 [...] Call Trace: ? kasan_free_pages+0x50/0x60 free_hot_cold_page+0x382/0x9e0 [...] __free_pages+0xe8/0x100 [...] __free_pages_bootmem+0x1c9/0x202 ? page_alloc_init_late+0x3a/0x3a ? kmemleak_free_part+0x42/0x150 free_bootmem_late+0x5f/0x7d efi_free_boot_services+0x10d/0x233 [...] Fix this by making vmemmap_populate_basepages() round the start argument down to a multiple of PAGE_SIZE such that the above condition can never hold. Signed-off-by: Nicolai Stange --- mm/sparse-vmemmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index 8679d4a81b98..d45bd2714a2b 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -223,7 +223,7 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end, int node) { - unsigned long addr = start; + unsigned long addr = start & ~(PAGE_SIZE - 1); pgd_t *pgd; pud_t *pud; pmd_t *pmd; -- 2.11.1 -- 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