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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 92810C433E0 for ; Thu, 18 Mar 2021 00:31:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D863664E74 for ; Thu, 18 Mar 2021 00:31:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D863664E74 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2E5BE6B0070; Wed, 17 Mar 2021 20:31:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2BADD6B0071; Wed, 17 Mar 2021 20:31:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 182086B0072; Wed, 17 Mar 2021 20:31:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0091.hostedemail.com [216.40.44.91]) by kanga.kvack.org (Postfix) with ESMTP id F3BCD6B0070 for ; Wed, 17 Mar 2021 20:31:00 -0400 (EDT) Received: from smtpin32.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AE8A11E15 for ; Thu, 18 Mar 2021 00:31:00 +0000 (UTC) X-FDA: 77931115080.32.CE02284 Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) by imf25.hostedemail.com (Postfix) with ESMTP id 373786000110 for ; Thu, 18 Mar 2021 00:31:00 +0000 (UTC) Received: by mail-pj1-f41.google.com with SMTP id bt4so1993138pjb.5 for ; Wed, 17 Mar 2021 17:30:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=GkuRWpW9bExkYFxOTvvebzKRarhbJmzTDiFRajMJb68=; b=Tw1JOhx9WMaxj2zgL2+u0rROy7M24TONLFY0jAeGeUZ8wvui68EopwXxn0qUW0MLd0 7wDivc0uuetGtGIEBWlrqWFTBrilHFV2627ljgT263GE3RoDzgfyK5e5EBpYudqtz3dd /GlEBbuxEmry+CKUqSgiqaef06Dd3YyED+Uy8aI1BWqYM3LFXERUI3TDN2+wCbHzSCrC kocqgtsBmdIspMmdXpz5DCNo6LQRcOt+khcnBdBCVCCRtYuHidggrt5eRg0wTtuaDlgX W3kktFufFg0ZZSamAU5eWzJAmxbxOAlnl292ZmodwTRQBmd9GRSUIOVk5WemXVV5R2pn lMmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=GkuRWpW9bExkYFxOTvvebzKRarhbJmzTDiFRajMJb68=; b=GQ4mK0GZYLj5a+q+8icqAlMIBo+I2te8JD1yluAMa+REkX56pxyc8KXTqffSGjol/U SM4CiHzmpEYT6ZOczaodSOBnkVXUrWRC0ezobg8KDaDv4QzueVQ6C3V59XtvnFLxiQwp /i3/pTmYL3sQTirZe440ZrfdMH9Ojb6QyZ8cU4lRtzf7EOHJcbfU3R+MpeKLykM1DEvQ C+I2kRqCYu0USSvbPTQ94XcPNmKVfouuP73dUOTZvjSiMKldDdnDqiPJYhs+jCgGHyNX jpReU6Ru6Jm5yq6S/I0Bh+IGRpZkTBrQv26BCdL7uqut8uBgTgwmCZELWKOYwOLcvLKv pJYQ== X-Gm-Message-State: AOAM530uOvhUznEev1tmaJB4LXGvqLnZMXCSdZ+8MT0etCJEnh/18KMv CvJV8tmJU8096DD4dhRQK2hwdz8zJ4yXqwDm93hBxw== X-Google-Smtp-Source: ABdhPJzesTshIrJdKNHCDmlj2OR3e0xSraSKUZZ3Bj14Xck17fx++XRNX8MVNVTQU2DyspV0entCrOLh4c3wfRmf7Lw= X-Received: by 2002:a17:90a:a10c:: with SMTP id s12mr1413387pjp.166.1616027458725; Wed, 17 Mar 2021 17:30:58 -0700 (PDT) MIME-Version: 1.0 References: <20210316024410.19967-1-walter-zh.wu@mediatek.com> In-Reply-To: <20210316024410.19967-1-walter-zh.wu@mediatek.com> From: Andrey Konovalov Date: Thu, 18 Mar 2021 01:30:47 +0100 Message-ID: Subject: Re: [PATCH v2] task_work: kasan: record task_work_add() call stack To: Walter Wu Cc: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Matthias Brugger , Andrew Morton , Jens Axboe , Oleg Nesterov , kasan-dev , Linux Memory Management List , LKML , Linux ARM , wsd_upstream , "moderated list:ARM/Mediatek SoC..." Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: fugic381q88rteqabm75h3phez4xgne7 X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 373786000110 Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf25; identity=mailfrom; envelope-from=""; helo=mail-pj1-f41.google.com; client-ip=209.85.216.41 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1616027460-798968 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 16, 2021 at 3:44 AM Walter Wu wrote: > > 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 Konovalov > Cc: Andrey Ryabinin > Cc: Dmitry Vyukov > Cc: Alexander Potapenko > Cc: Andrew Morton > Cc: Matthias Brugger > Cc: Jens Axboe > Cc: Oleg Nesterov > --- > > v2: Fix kasan_record_aux_stack() calling sequence issue. > Thanks for Dmitry's suggestion > > --- > 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..3d4852891fa8 100644 > --- a/kernel/task_work.c > +++ b/kernel/task_work.c > @@ -34,6 +34,9 @@ int task_work_add(struct task_struct *task, struct callback_head *work, > { > struct callback_head *head; > > + /* record the work call stack in order to print it in KASAN reports */ > + kasan_record_aux_stack(work); > + > do { > head = READ_ONCE(task->task_works); > if (unlikely(head == &work_exited)) > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index 3436c6bf7c0c..e4629a971a3c 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. > + * The 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]; > -- Acked-by: Andrey Konovalov