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[141.239.159.203]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1fac1569660sm639845ad.231.2024.06.27.11.29.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Jun 2024 11:29:34 -0700 (PDT) Sender: Tejun Heo Date: Thu, 27 Jun 2024 08:29:33 -1000 From: Tejun Heo To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: Chen Ridong , lizefan.x@bytedance.com, hannes@cmpxchg.org, longman@redhat.com, adityakali@google.com, sergeh@kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3] cgroup/cpuset: Prevent UAF in proc_cpuset_show() Message-ID: References: <20240626094101.472912-1-chenridong@huawei.com> <6mjie6enbm5ltei4fsanz64ofukbr4gvss7ywi5sjfjxjxing7@efuhtnqvfawd> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <6mjie6enbm5ltei4fsanz64ofukbr4gvss7ywi5sjfjxjxing7@efuhtnqvfawd> Hello, On Thu, Jun 27, 2024 at 11:46:10AM +0200, Michal Koutný wrote: > Your patch should work thanks to the rcu_read_lock and > cgroup_free_root/kfree_rcu and the `if (css->cgroup)` guard is > unnecessary. > > So the patch is a functional fix, the reasoning in commit message is > little off. Not sure if Tejun rebases his for-6.10-fixes (with a > possible v4), full fixup commit for this may not be worthy. This one's on the top. If Chen can send me a patch with updated description, I will replace the patch. Thanks. -- tejun