From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9C76C4360F for ; Thu, 4 Apr 2019 09:09:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BAAB220693 for ; Thu, 4 Apr 2019 09:09:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554368955; bh=Y6q5uWmJqjzqEdywjipgNwO0vbLAPX/JdRS21f+zOYA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Yk2VFumHUrt1dihmLRYejFC6rvHRzKmHjVVitoATFpvvs2KxR52+UWm9SvOgQWmQ5 yOVrSzXkpojyrA9Ld7HnGrbbKBd/Qzs3YlnD9fHmXkUm6kE2pL0f8ebCPIteDmPjWQ h8Q+UylhyvM0cHeesoSmjB0nM++ftshCMwfR1iyw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732363AbfDDJJO (ORCPT ); Thu, 4 Apr 2019 05:09:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:48228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731213AbfDDJJH (ORCPT ); Thu, 4 Apr 2019 05:09:07 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F1B802054F; Thu, 4 Apr 2019 09:09:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554368946; bh=Y6q5uWmJqjzqEdywjipgNwO0vbLAPX/JdRS21f+zOYA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x3luxSkK3uE8MXEQ/rjHM+js8NX+67XKsQSBZcdzUZWxSDkRMILeCLgjFC7KIyN1t 3dpUMtJfwEhrrkWgMjGoDezyc5HOMi4L9vd2Xf2Uv/RTHcf9eQp6XBVtbooDw4LdoB 2PUp71Madr1MTGn9O3+OXIxF0f20LaSyMi0thJPs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qian Cai , Andrey Ryabinin , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 5.0 040/246] page_poison: play nicely with KASAN Date: Thu, 4 Apr 2019 10:45:40 +0200 Message-Id: <20190404084620.443265908@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190404084619.236418459@linuxfoundation.org> References: <20190404084619.236418459@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 5.0-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 4117992df66a26fa33908b4969e04801534baab1 ] KASAN does not play well with the page poisoning (CONFIG_PAGE_POISONING). It triggers false positives in the allocation path: BUG: KASAN: use-after-free in memchr_inv+0x2ea/0x330 Read of size 8 at addr ffff88881f800000 by task swapper/0 CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc1+ #54 Call Trace: dump_stack+0xe0/0x19a print_address_description.cold.2+0x9/0x28b kasan_report.cold.3+0x7a/0xb5 __asan_report_load8_noabort+0x19/0x20 memchr_inv+0x2ea/0x330 kernel_poison_pages+0x103/0x3d5 get_page_from_freelist+0x15e7/0x4d90 because KASAN has not yet unpoisoned the shadow page for allocation before it checks memchr_inv() but only found a stale poison pattern. Also, false positives in free path, BUG: KASAN: slab-out-of-bounds in kernel_poison_pages+0x29e/0x3d5 Write of size 4096 at addr ffff8888112cc000 by task swapper/0/1 CPU: 5 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc1+ #55 Call Trace: dump_stack+0xe0/0x19a print_address_description.cold.2+0x9/0x28b kasan_report.cold.3+0x7a/0xb5 check_memory_region+0x22d/0x250 memset+0x28/0x40 kernel_poison_pages+0x29e/0x3d5 __free_pages_ok+0x75f/0x13e0 due to KASAN adds poisoned redzones around slab objects, but the page poisoning needs to poison the whole page. Link: http://lkml.kernel.org/r/20190114233405.67843-1-cai@lca.pw Signed-off-by: Qian Cai Acked-by: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/page_alloc.c | 2 +- mm/page_poison.c | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 11dc3c0e8728..20dd3283bb1b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1945,8 +1945,8 @@ inline void post_alloc_hook(struct page *page, unsigned int order, arch_alloc_page(page, order); kernel_map_pages(page, 1 << order, 1); - kernel_poison_pages(page, 1 << order, 1); kasan_alloc_pages(page, order); + kernel_poison_pages(page, 1 << order, 1); set_page_owner(page, order, gfp_flags); } diff --git a/mm/page_poison.c b/mm/page_poison.c index f0c15e9017c0..21d4f97cb49b 100644 --- a/mm/page_poison.c +++ b/mm/page_poison.c @@ -6,6 +6,7 @@ #include #include #include +#include static bool want_page_poisoning __read_mostly; @@ -40,7 +41,10 @@ static void poison_page(struct page *page) { void *addr = kmap_atomic(page); + /* KASAN still think the page is in-use, so skip it. */ + kasan_disable_current(); memset(addr, PAGE_POISON, PAGE_SIZE); + kasan_enable_current(); kunmap_atomic(addr); } -- 2.19.1