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=-18.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 A0EE7C43387 for ; Tue, 8 Jan 2019 19:28:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7254220883 for ; Tue, 8 Jan 2019 19:28:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546975702; bh=XkMQf4LAbIuz/s2TQsGvtiE2p6kdQ9tDek5GOtkdnxo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Zsc9CsbqUdU+KePiEgHtaKhQ+mRQIUOGSiNW9V7Gu++uWxh5rTOx2kJPxorO9TAxy sg/tibbEcaYcDkIzmWKQviKmVCHBU0xNtcHu67H7Qv6EcCzjWdvqu9MFXkbucCvsjN DpcpS/vn6KfdzjBCWeDYjW+iuaMX4prKZFmuXLjQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729995AbfAHT2V (ORCPT ); Tue, 8 Jan 2019 14:28:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:35260 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729976AbfAHT2S (ORCPT ); Tue, 8 Jan 2019 14:28:18 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CCEBD20665; Tue, 8 Jan 2019 19:28:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546975697; bh=XkMQf4LAbIuz/s2TQsGvtiE2p6kdQ9tDek5GOtkdnxo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ML2+ofL+o6mH8DXtfYtJdcdKYO8mi3/O+PzwAruCek8c6hzj00qKpH98OFgzjXX1V 8gaqa+pNY7FyY9ZhB7nVJw7LCTmmawgBeCZrmyKdPvmq/nGErjn0d6zEFFP2n15c6U EZ4av1lm8K7SxoWOq4Zsw1tyOy9AceFV1rdoCYdo= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Qian Cai , Will Deacon , Sasha Levin Subject: [PATCH AUTOSEL 4.20 061/117] arm64: kasan: Increase stack size for KASAN_EXTRA Date: Tue, 8 Jan 2019 14:25:29 -0500 Message-Id: <20190108192628.121270-61-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190108192628.121270-1-sashal@kernel.org> References: <20190108192628.121270-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qian Cai [ Upstream commit 6e8830674ea77f57d57a33cca09083b117a71f41 ] If the kernel is configured with KASAN_EXTRA, the stack size is increased significantly due to setting the GCC -fstack-reuse option to "none" [1]. As a result, it can trigger a stack overrun quite often with 32k stack size compiled using GCC 8. For example, this reproducer https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/madvise/madvise06.c can trigger a "corrupted stack end detected inside scheduler" very reliably with CONFIG_SCHED_STACK_END_CHECK enabled. There are other reports at: https://lore.kernel.org/lkml/1542144497.12945.29.camel@gmx.us/ https://lore.kernel.org/lkml/721E7B42-2D55-4866-9C1A-3E8D64F33F9C@gmx.us/ There are just too many functions that could have a large stack with KASAN_EXTRA due to large local variables that have been called over and over again without being able to reuse the stacks. Some noticiable ones are, size 7536 shrink_inactive_list 7440 shrink_page_list 6560 fscache_stats_show 3920 jbd2_journal_commit_transaction 3216 try_to_unmap_one 3072 migrate_page_move_mapping 3584 migrate_misplaced_transhuge_page 3920 ip_vs_lblcr_schedule 4304 lpfc_nvme_info_show 3888 lpfc_debugfs_nvmestat_data.constprop There are other 49 functions over 2k in size while compiling kernel with "-Wframe-larger-than=" on this machine. Hence, it is too much work to change Makefiles for each object to compile without -fsanitize-address-use-after-scope individually. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715#c23 Signed-off-by: Qian Cai Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/include/asm/memory.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index f0a5c9531e8b..778af0b7f7fd 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -67,12 +67,17 @@ /* * KASAN requires 1/8th of the kernel virtual address space for the shadow * region. KASAN can bloat the stack significantly, so double the (minimum) - * stack size when KASAN is in use. + * stack size when KASAN is in use, and then double it again if KASAN_EXTRA is + * on. */ #ifdef CONFIG_KASAN #define KASAN_SHADOW_SCALE_SHIFT 3 #define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT)) +#ifdef CONFIG_KASAN_EXTRA +#define KASAN_THREAD_SHIFT 2 +#else #define KASAN_THREAD_SHIFT 1 +#endif /* CONFIG_KASAN_EXTRA */ #else #define KASAN_SHADOW_SIZE (0) #define KASAN_THREAD_SHIFT 0 -- 2.19.1