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[92.236.12.48]) by smtp.gmail.com with ESMTPSA id v27sm17541973wrv.81.2020.06.06.08.45.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 06 Jun 2020 08:45:12 -0700 (PDT) From: Jonny Grant Subject: Re: core(5) To: Jakub Wilk Cc: Michael Kerrisk , linux-man@vger.kernel.org References: <9000a831-9a0f-0577-5755-95b301218383@jguk.org> <20200606145003.x37j5hywuyn32lpf@jwilk.net> Message-ID: Date: Sat, 6 Jun 2020 16:45:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200606145003.x37j5hywuyn32lpf@jwilk.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit Sender: linux-man-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org On 06/06/2020 15:50, Jakub Wilk wrote: > * Jonny Grant , 2020-06-06, 14:18: >> 3) Could i ask to clarify my understanding. For this "The binary being executed by the process does not have read >>          permission enabled." >> -- is this when the binary permissions are changed after it starts running? > > No, AFAICS the permission check is done when the process starts. How can the process start if the binary file doesn't have read permissions enabled? >> 4) I noticed %P always gave me P1200 even after a reboot I recall, I had expected it be '1', do you see similar? > > Here %P expands to the pid of the process, as expected: > >   $ uname -rv >   5.6.0-2-amd64 #1 SMP Debian 5.6.14-1 (2020-05-23) > >   $ sudo sysctl -w kernel.core_pattern="%P-%e-%s.core" >   kernel.core_pattern = %P-%e-%s.core > >   $ ulimit -c unlimited > >   $ sh -c 'kill -ABRT $$' >   Aborted (core dumped) > >   $ ls *.core >   7154-sh-6.core My apologies, it was P1000. This was from two different runs, 2 days apart. I think this was "P%P-T%i%e-%s-T%t". I tried to reproduce today, but couldn't -rw------- 1 jonny jonny 99041280 May 27 21:42 P1000-T18441Process-5-T1590612166.core -rw------- 1 jonny jonny 104407040 May 29 23:24 P1000-T5804Process-5-T1590791098.core Cheers, Jonny