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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id o190sm869295pfb.178.2020.05.08.00.30.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 May 2020 00:30:14 -0700 (PDT) Date: Fri, 8 May 2020 00:30:13 -0700 From: Kees Cook To: Michael Ellerman Cc: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] selftests/lkdtm: Don't clear dmesg when running tests Message-ID: <202005080029.538E27C@keescook> References: <20200508065356.2493343-1-mpe@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200508065356.2493343-1-mpe@ellerman.id.au> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 08, 2020 at 04:53:55PM +1000, Michael Ellerman wrote: > It is Very Rude to clear dmesg in test scripts. That's because the > script may be part of a larger test run, and clearing dmesg > potentially destroys the output of other tests. > > We can avoid using dmesg -c by saving the content of dmesg before the > test, and then using diff to compare that to the dmesg afterward, > producing a log with just the added lines. Sounds good to me! > > Signed-off-by: Michael Ellerman Acked-by: Kees Cook -- Kees Cook