From patchwork Mon Aug 13 13:19:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 956974 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 41pxGn42L5z9s7c for ; Mon, 13 Aug 2018 23:22:25 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 41pxGn2pHqzF0WR for ; Mon, 13 Aug 2018 23:22:25 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 41pxCz4pJ9zDr5t for ; Mon, 13 Aug 2018 23:19:58 +1000 (AEST) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 41pxCr1Hbcz9tvRK; Mon, 13 Aug 2018 15:19:52 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 1OxWcrXYM-QL; Mon, 13 Aug 2018 15:19:52 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 41pxCr0qwxz9tvRJ; Mon, 13 Aug 2018 15:19:52 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id B9CEC8B7A7; Mon, 13 Aug 2018 15:19:52 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id UOgeQgf-16L2; Mon, 13 Aug 2018 15:19:52 +0200 (CEST) Received: from pc16082vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.231.4]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9B7078B752; Mon, 13 Aug 2018 15:19:52 +0200 (CEST) Received: by pc16082vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 5523C7125D; Mon, 13 Aug 2018 13:19:52 +0000 (UTC) Message-Id: From: Christophe Leroy Subject: [PATCH] powerpc/mm: Don't report hugepage tables as memory leaks when using kmemleak To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Date: Mon, 13 Aug 2018 13:19:52 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" When a process allocates a hugepage, the following leak is reported by kmemleak. This is a false positive which is due to the pointer to the table being stored in the PGD as physical memory address and not virtual memory pointer. unreferenced object 0xc30f8200 (size 512): comm "mmap", pid 374, jiffies 4872494 (age 627.630s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] huge_pte_alloc+0xdc/0x1f8 [<9e0df1e1>] hugetlb_fault+0x560/0x8f8 [<7938ec6c>] follow_hugetlb_page+0x14c/0x44c [] __get_user_pages+0x1c4/0x3dc [] __mm_populate+0xac/0x140 [<3215421e>] vm_mmap_pgoff+0xb4/0xb8 [] ksys_mmap_pgoff+0xcc/0x1fc [<4fcd760f>] ret_from_syscall+0x0/0x38 See commit a984506c542e2 ("powerpc/mm: Don't report PUDs as memory leaks when using kmemleak") for detailed explanation. To fix that, this patch tells kmemleak to ignore the allocated hugepage table. Signed-off-by: Christophe Leroy --- arch/powerpc/mm/hugetlbpage.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index e87f9ef9115b..7296a42eb62e 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -112,6 +113,8 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, for (i = i - 1 ; i >= 0; i--, hpdp--) *hpdp = __hugepd(0); kmem_cache_free(cachep, new); + } else { + kmemleak_ignore(new); } spin_unlock(ptl); return 0;