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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_RED, 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 CF351C433DB for ; Mon, 15 Mar 2021 02:06:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BBE464E46 for ; Mon, 15 Mar 2021 02:06:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229865AbhCOCFq (ORCPT ); Sun, 14 Mar 2021 22:05:46 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:35315 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S229767AbhCOCFP (ORCPT ); Sun, 14 Mar 2021 22:05:15 -0400 X-UUID: ac1356e0c116491abcf4e1cd36c396f8-20210315 X-UUID: ac1356e0c116491abcf4e1cd36c396f8-20210315 Received: from mtkcas06.mediatek.inc [(172.21.101.30)] by mailgw02.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.14 Build 0819 with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1286494231; Mon, 15 Mar 2021 10:00:02 +0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs01n2.mediatek.inc (172.21.101.79) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 15 Mar 2021 09:59:46 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 15 Mar 2021 09:59:46 +0800 From: Walter Wu To: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Matthias Brugger , Andrey Konovalov , "Andrew Morton" , Jens Axboe , "Oleg Nesterov" CC: , , , , wsd_upstream , , Walter Wu Subject: [PATCH] task_work: kasan: record task_work_add() call stack Date: Mon, 15 Mar 2021 09:59:40 +0800 Message-ID: <20210315015940.11788-1-walter-zh.wu@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 Content-Type: text/plain X-TM-SNTS-SMTP: 9DA2466084124075C1C17447C85E61ECA4CB0544570674D733F2D6BE08A8DDD32000:8 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Why record task_work_add() call stack? Syzbot reports many use-after-free issues for task_work, see [1]. After see the free stack and the current auxiliary stack, we think they are useless, we don't know where register the work, this work may be the free call stack, so that we miss the root cause and don't solve the use-after-free. Add task_work_add() call stack into KASAN auxiliary stack in order to improve KASAN report. It is useful for programmers to solve use-after-free issues. [1]: https://groups.google.com/g/syzkaller-bugs/search?q=kasan%20use-after-free%20task_work_run Signed-off-by: Walter Wu Suggested-by: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Andrey Konovalov Cc: Alexander Potapenko Cc: Andrew Morton Cc: Matthias Brugger Cc: Jens Axboe Cc: Oleg Nesterov --- kernel/task_work.c | 3 +++ mm/kasan/kasan.h | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/task_work.c b/kernel/task_work.c index 9cde961875c0..f255294377da 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -55,6 +55,9 @@ int task_work_add(struct task_struct *task, struct callback_head *work, break; } + /* record the work call stack in order to print it in KASAN reports */ + kasan_record_aux_stack(work); + return 0; } diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 3436c6bf7c0c..d300fe9415bd 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -146,7 +146,7 @@ struct kasan_alloc_meta { struct kasan_track alloc_track; #ifdef CONFIG_KASAN_GENERIC /* - * call_rcu() call stack is stored into struct kasan_alloc_meta. + * Auxiliary stack is stored into struct kasan_alloc_meta. * The free stack is stored into struct kasan_free_meta. */ depot_stack_handle_t aux_stack[2]; -- 2.18.0