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Mon, 17 Apr 2023 11:46:53 -0700 (PDT) Received: from [192.168.0.160] ([170.253.51.134]) by smtp.gmail.com with ESMTPSA id q13-20020adfcd8d000000b002e51195a3e2sm11098120wrj.79.2023.04.17.11.46.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Apr 2023 11:46:53 -0700 (PDT) Message-ID: <88991b38-26f5-e060-3a29-5f17c5fc85df@gmail.com> Date: Mon, 17 Apr 2023 20:46:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: Checking for support of ptrace(PTRACE_SEIZE,...) on older kernels Content-Language: en-US To: Oleg Nesterov Cc: Sergei Zhirikov , linux-man@vger.kernel.org, LKML References: <997950238.3486335.1681414225118.ref@mail.yahoo.com> <997950238.3486335.1681414225118@mail.yahoo.com> <0d95a96b-dd49-db45-ab3c-1d9cee51381d@gmail.com> <20230417115009.GA906@redhat.com> From: Alejandro Colomar In-Reply-To: <20230417115009.GA906@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------03r7NMpvI9fyCsHllq8xf7Cs" Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --------------03r7NMpvI9fyCsHllq8xf7Cs Content-Type: multipart/mixed; boundary="------------fHhULJne82m7Do3fon0zhWTb"; protected-headers="v1" From: Alejandro Colomar To: Oleg Nesterov Cc: Sergei Zhirikov , linux-man@vger.kernel.org, LKML Message-ID: <88991b38-26f5-e060-3a29-5f17c5fc85df@gmail.com> Subject: Re: Checking for support of ptrace(PTRACE_SEIZE,...) on older kernels References: <997950238.3486335.1681414225118.ref@mail.yahoo.com> <997950238.3486335.1681414225118@mail.yahoo.com> <0d95a96b-dd49-db45-ab3c-1d9cee51381d@gmail.com> <20230417115009.GA906@redhat.com> In-Reply-To: <20230417115009.GA906@redhat.com> --------------fHhULJne82m7Do3fon0zhWTb Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Oleg, On 4/17/23 13:50, Oleg Nesterov wrote: > Well, from https://man7.org/linux/man-pages/man2/ptrace.2.html >=20 > ESRCH The specified process does not exist, or is not currently= > being traced by the caller, or is not stopped (for > requests that require a stopped tracee). >=20 > so if the kernel doesn't support PTRACE_SEIZE then ptrace(PTRACE_SEIZE)= > should fail with -ESRCH as documented. >=20 > Perhaps this part >=20 > EIO request is invalid, or ... >=20 > can be improvef a bit to explain that this happens if the target is alr= eady > traced by us and stopped. I'm not sure if it's necessary. When several errors happen at the same t= ime, there's usually no documentation about which takes precedence, with few exceptions. Knowing it's intentional, I'm content. Thanks, Alex --=20 GPG key fingerprint: A9348594CE31283A826FBDD8D57633D441E25BB5 --------------fHhULJne82m7Do3fon0zhWTb-- --------------03r7NMpvI9fyCsHllq8xf7Cs Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE6jqH8KTroDDkXfJAnowa+77/2zIFAmQ9lBsACgkQnowa+77/ 2zL59Q//X28ctGScdrEJzDoIicoxyQQ//Xd9l+LjF2dAYgiOQIhKaBQsVA8WmErh 24JyCCTdOnxxTjUhZN4O0BHrE/0Cz6oRqgzur+sgtu8+HO/1eVqIn0QciGM8Zx4C AHWsfouxVsztXd0NNK67IbuZhWnfunSwf72EjH4bPQI7gd6pvXTJuYJZ9yBVEcpk CsK4JHK4bRMicq8lXUxBNMaPo4/iaDCv7Cnfkdrpc4eXlKdjeELIHte59io1sY19 DK7Dm13xY0AqAtcUMzvJV73u4HGvDGVIPR1zTrSO3ckjKS4PwyyVldCMSlSvWN/o vyTKFfwWpVwkn7RM8xS3w2Fy2Gm8ONLtpdhhm3KR5vCAXue3BXZCnGvpd6bpngtY 8NHRkHMMk0aw3xe6HuDAWqHGzLqqPoLH05B5A+KirDXlzzY09PGJY51KwcqhWpwJ SqnOq7qXPB0Ku6BEYIJGOSOZDNhrfNd1CGp9IZFtBFBcKi/e5Yviz1SvLRrM67/f uHO9d+WWBGFTMKKQ72rT20AglYH08crixU0uyRkS2MCsokiO47yvKrnT3UMWHzdZ XUFqJGVf6w2x5Tn9sFbIet4XPHiNPv+Cnj51B5X2w/UU3Q5GrVLuNURyFf2oJ9QQ QCRrQGGjpY1Tyuuu8iFbAQOncpn6J0SOJTSFqfe5Rrolg7/b2zU= =MrCo -----END PGP SIGNATURE----- --------------03r7NMpvI9fyCsHllq8xf7Cs--