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[72.235.13.41]) by smtp.gmail.com with ESMTPSA id mp15-20020a17090b190f00b00265c742a262sm8860419pjb.4.2023.09.19.10.42.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Sep 2023 10:42:40 -0700 (PDT) Sender: Tejun Heo Date: Tue, 19 Sep 2023 07:42:39 -1000 From: Tejun Heo To: Zqiang Cc: jiangshanlai@gmail.com, syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] workqueue: Fix UAF report by KASAN in pwq_release_workfn() Message-ID: References: <20230919081958.7071-1-qiang.zhang1211@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230919081958.7071-1-qiang.zhang1211@gmail.com> X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE, SPF_PASS autolearn=no 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 X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Tue, 19 Sep 2023 10:44:58 -0700 (PDT) Hello, The patch looks fine but On Tue, Sep 19, 2023 at 04:19:58PM +0800, Zqiang wrote: > @@ -4743,6 +4743,8 @@ struct workqueue_struct *alloc_workqueue(const char *fmt, > wq_free_lockdep(wq); > err_free_wq: > free_workqueue_attrs(wq->unbound_attrs); Can you please add a comment here explaining why the flushing is necessary? > + if (wq->flags & WQ_UNBOUND) > + kthread_flush_worker(pwq_release_worker); Thanks. -- tejun