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[24.205.208.113]) by smtp.gmail.com with ESMTPSA id u20-20020a05620a455400b0067ec0628661sm261739qkp.110.2022.03.23.09.17.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 23 Mar 2022 09:17:38 -0700 (PDT) Subject: Re: [PATCH v2] livepatch: Reorder to use before freeing a pointer To: Petr Mladek Cc: jpoimboe@redhat.com, jikos@kernel.org, mbenes@suse.cz, joe.lawrence@redhat.com, nathan@kernel.org, ndesaulniers@google.com, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev References: <20220320015143.2208591-1-trix@redhat.com> From: Tom Rix Message-ID: Date: Wed, 23 Mar 2022 09:17:35 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/23/22 8:53 AM, Petr Mladek wrote: > On Sat 2022-03-19 18:51:43, trix@redhat.com wrote: >> From: Tom Rix >> >> Clang static analysis reports this issue >> livepatch-shadow-fix1.c:113:2: warning: Use of >> memory after it is freed >> pr_info("%s: dummy @ %p, prevented leak @ %p\n", >> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> >> The pointer is freed in the previous statement. >> Reorder the pr_info to report before the free. >> >> Similar issue in livepatch-shadow-fix2.c > I have added the following paragraph: > > > Note that it is a false positive. pr_info() just prints the address. > The freed memory is not accessed. Well, the static analyzer could not > know this easily. > > >> Signed-off-by: Tom Rix > and pushed the patch into livepatching/livepatching.git, > branch for-5.18/selftests-fixes. > > IMHO, the patch is so trivial and can be added even in this merge > window. There is no need to create more dances around it ;-) > > Let me know if you disagree. I am going to send the pull request > on Friday or Monday. Do whatever is easier for you.  The addition to the commit log is fine. Thanks Tom > > Best Regards, > Petr >