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[2620:137:e000::1:20]) by mx.google.com with ESMTP id w16-20020a056402269000b0041978294066si1673575edd.275.2022.04.15.09.05.26; Fri, 15 Apr 2022 09:05:59 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239641AbiDNR3e (ORCPT + 99 others); Thu, 14 Apr 2022 13:29:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237156AbiDNR3c (ORCPT ); Thu, 14 Apr 2022 13:29:32 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A690C9B4E for ; Thu, 14 Apr 2022 10:27:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id BD37BB8217B for ; Thu, 14 Apr 2022 17:27:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BFD2C385A5; Thu, 14 Apr 2022 17:26:59 +0000 (UTC) Date: Thu, 14 Apr 2022 18:26:56 +0100 From: Catalin Marinas To: Patrick Wang Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: kmemleak: take a full lowmem check in kmemleak_*_phys() Message-ID: References: <20220413122925.33856-1-patrick.wang.shcn@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220413122925.33856-1-patrick.wang.shcn@gmail.com> X-Spam-Status: No, score=-6.7 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 13, 2022 at 08:29:25PM +0800, Patrick Wang wrote: > The kmemleak_*_phys() apis do not check the address for lowmem's min > boundary, while the caller may pass an address below lowmem, which > will trigger an oops: > > # echo scan > /sys/kernel/debug/kmemleak > [ 54.888353] Unable to handle kernel paging request at virtual address ff5fffffffe00000 > [ 54.888932] Oops [#1] > [ 54.889102] Modules linked in: > [ 54.889326] CPU: 2 PID: 134 Comm: bash Not tainted 5.18.0-rc1-next-20220407 #33 > [ 54.889620] Hardware name: riscv-virtio,qemu (DT) > [ 54.889901] epc : scan_block+0x74/0x15c > [ 54.890215] ra : scan_block+0x72/0x15c > [ 54.890390] epc : ffffffff801e5806 ra : ffffffff801e5804 sp : ff200000104abc30 > [ 54.890607] gp : ffffffff815cd4e8 tp : ff60000004cfa340 t0 : 0000000000000200 > [ 54.890835] t1 : 00aaaaaac23954cc t2 : 00000000000003ff s0 : ff200000104abc90 > [ 54.891024] s1 : ffffffff81b0ff28 a0 : 0000000000000000 a1 : ff5fffffffe01000 > [ 54.891201] a2 : ffffffff81b0ff28 a3 : 0000000000000002 a4 : 0000000000000001 > [ 54.891377] a5 : 0000000000000000 a6 : ff200000104abd7c a7 : 0000000000000005 > [ 54.891552] s2 : ff5fffffffe00ff9 s3 : ffffffff815cd998 s4 : ffffffff815d0e90 > [ 54.891727] s5 : ffffffff81b0ff28 s6 : 0000000000000020 s7 : ffffffff815d0eb0 > [ 54.891903] s8 : ffffffffffffffff s9 : ff5fffffffe00000 s10: ff5fffffffe01000 > [ 54.892078] s11: 0000000000000022 t3 : 00ffffffaa17db4c t4 : 000000000000000f > [ 54.892271] t5 : 0000000000000001 t6 : 0000000000000000 > [ 54.892408] status: 0000000000000100 badaddr: ff5fffffffe00000 cause: 000000000000000d > [ 54.892643] [] scan_gray_list+0x12e/0x1a6 > [ 54.892824] [] kmemleak_scan+0x2aa/0x57e > [ 54.892961] [] kmemleak_write+0x32a/0x40c > [ 54.893096] [] full_proxy_write+0x56/0x82 > [ 54.893235] [] vfs_write+0xa6/0x2a6 > [ 54.893362] [] ksys_write+0x6c/0xe2 > [ 54.893487] [] sys_write+0x22/0x2a > [ 54.893609] [] ret_from_syscall+0x0/0x2 Acked-by: Catalin Marinas