From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joey Pabalinas Subject: Re: Re: [PATCH RESEND v3 1/3] ptrace: pass type of a syscall-stop in ptrace_message Date: Sat, 24 Nov 2018 20:17:26 -1000 Message-ID: <20181125061726.jtalb5t4tgigzzue@gmail.com> References: <20181125022150.46258a20@akathisia> <20181125022227.55e8caf7@akathisia> <20181125015402.glcaw3kghcu4pr22@gmail.com> <20181125021059.GA1190@altlinux.org> Reply-To: strace development discussions Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1708076510611580316==" Return-path: In-Reply-To: <20181125021059.GA1190-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: strace-devel-bounces-3+4lAyCyj6AWlMsSdNXQLw@public.gmane.org Sender: "Strace-devel" To: "Dmitry V. Levin" Cc: Joey Pabalinas , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Oleg Nesterov , Steven Rostedt , Eugene Syromyatnikov , strace-devel-3+4lAyCyj6AWlMsSdNXQLw@public.gmane.org, Andy Lutomirski , Ingo Molnar , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org --===============1708076510611580316== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="4ktpenoxjmibnb6h" Content-Disposition: inline --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-- --===============1708076510611580316== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline -- Strace-devel mailing list Strace-devel-3+4lAyCyj6AWlMsSdNXQLw@public.gmane.org https://lists.strace.io/mailman/listinfo/strace-devel --===============1708076510611580316==--