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[98.150.136.16]) by smtp.gmail.com with ESMTPSA id f22-v6sm62742673pfn.177.2018.11.24.22.17.27 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 24 Nov 2018 22:17:28 -0800 (PST) Date: Sat, 24 Nov 2018 20:17:26 -1000 From: Joey Pabalinas To: "Dmitry V. Levin" Cc: Joey Pabalinas , Elvira Khabirova , Oleg Nesterov , Steven Rostedt , Ingo Molnar , Andy Lutomirski , Eugene Syromyatnikov , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, strace-devel@lists.strace.io Subject: Re: Re: [PATCH RESEND v3 1/3] ptrace: pass type of a syscall-stop in ptrace_message Message-ID: <20181125061726.jtalb5t4tgigzzue@gmail.com> Mail-Followup-To: Joey Pabalinas , "Dmitry V. Levin" , Elvira Khabirova , Oleg Nesterov , Steven Rostedt , Ingo Molnar , Andy Lutomirski , Eugene Syromyatnikov , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, strace-devel@lists.strace.io References: <20181125022150.46258a20@akathisia> <20181125022227.55e8caf7@akathisia> <20181125015402.glcaw3kghcu4pr22@gmail.com> <20181125021059.GA1190@altlinux.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="4ktpenoxjmibnb6h" Content-Disposition: inline In-Reply-To: <20181125021059.GA1190@altlinux.org> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --4ktpenoxjmibnb6h Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Nov 25, 2018 at 05:10:59AM +0300, Dmitry V. Levin wrote: > Given that without this patch the value returned by PTRACE_GETEVENTMSG > during syscall stop is undefined, we need two different ptrace_message > values that cannot be set by other ptrace events to enable reliable > identification of syscall-enter-stop and syscall-exit-stop in userspace: > if we make PTRACE_GETEVENTMSG return 0 or any other value routinely set by > other ptrace events, it would be hard for userspace to find out whether > the kernel implements new semantics or not. Ah, I see, I agree that definitely makes sense. --=20 Cheers, Joey Pabalinas --4ktpenoxjmibnb6h Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEENpTlWU2hUK/KMvHp2rGdfm9DtVIFAlv6PnUACgkQ2rGdfm9D tVLTKBAAwZqcHYLXU10sq1ZI/dIsYmjVmsCSC7bhuxjAi3cVnkw89BqlbTBfl8s5 bJcVhmPayYWCWE2paglX31lp1DKKtvWiFkbLE2jF601rAYekH69ty5Qvx8DMcrQV Ar2rnb8KECJE7pf9Fdexpx+FyhaM6wkj04YkysMOSEBbBA5ue4pSA5yIkO142jqw WRlqYBwYqGkNXWW74Ea8ZNEFPZxMrvBtI2olwqEs99erNGpTcafuchTAhdrKuDKZ 62zQEnD229IDXeLZV5+rbbyT7UiWb2xuw/xcOreCRhd8EArxgvFc5VcuywHTI6DM nPhWsvw7+XUXHpq406m5mLMq1TJMUwrCw+wQjfmaLvehOm+p16z9F3nsjAvUU/ez bGbTpgv/315EVtm8nqWl1s6pbBgK9cxnIl1DFmKptWbIl96FlSTCo1cOS4fRUNUC 1pgAUh2sVTxuTdARAmTkfKOmj1WoVnVJ+qke+0j/Knye9poolvZngb0PgaKdEwps i3Wq3OSv7OUGjwIPlYy3oAblfZpC4mhDe9uV+ytzGWfqJoY4hcyXAVOL6rXHx9ih XxnxIMd/vpKyc882gzKZ3wc6JOMl2QdJ2nPwb9OeK6qls3csaCHWa9ty4+tnUitk nbN53QvbmBiGDHJjTa6Tj9Lu40Buguhoipqu38ynV18XuUrKKQQ= =yO6t -----END PGP SIGNATURE----- --4ktpenoxjmibnb6h--