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Tue, 16 Mar 2021 07:33:21 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id d22sm8423199iof.48.2021.03.16.07.33.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Mar 2021 07:33:21 -0700 (PDT) Subject: Re: [PATCH v2] task_work: kasan: record task_work_add() call stack To: Walter Wu , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Matthias Brugger , Andrey Konovalov , Andrew Morton , Oleg Nesterov Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, wsd_upstream , linux-mediatek@lists.infradead.org References: <20210316024410.19967-1-walter-zh.wu@mediatek.com> From: Jens Axboe Message-ID: <7d5b6e38-2e11-06f7-0a6b-356bdda0cd5b@kernel.dk> Date: Tue, 16 Mar 2021 08:33:20 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210316024410.19967-1-walter-zh.wu@mediatek.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Stat-Signature: e8kxm48ht49mqy5rebdywc6ygu3sfyrc X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: AD9073F8 Received-SPF: none (kernel.dk>: No applicable sender policy available) receiver=imf20; identity=mailfrom; envelope-from=""; helo=mail-io1-f44.google.com; client-ip=209.85.166.44 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615905212-988975 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 3/15/21 8:44 PM, 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. I think this is a very useful addition, especially as task_work proliferates. Reviewed-by: Jens Axboe -- Jens Axboe