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From: "Dmitry V. Levin" <ldv-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org>
To: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Jann Horn <jannh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
	Eugene Syromyatnikov
	<esyr-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	strace-devel-3+4lAyCyj6AWlMsSdNXQLw@public.gmane.org
Subject: Re: [PATCH v4 1/2] ptrace: save the type of syscall-stop in ptrace_message
Date: Sat, 1 Dec 2018 01:53:50 +0300	[thread overview]
Message-ID: <20181130225350.GA8096@altlinux.org> (raw)
In-Reply-To: <20181130112920.GD23670-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>


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On Fri, Nov 30, 2018 at 12:29:21PM +0100, Oleg Nesterov wrote:
> On 11/30, Dmitry V. Levin wrote:
> > On Thu, Nov 29, 2018 at 03:47:43PM +0100, Oleg Nesterov wrote:
> >
> > > > so that PTRACE_GETEVENTMSG users can easily tell
> > > > whether this new semantics is supported by the kernel or not.
> > >
> > > Yes. And how much this can help? Again, an application can trivially detect
> > > if this feature implemented or not, and it should do this anyway if it wants
> > > to (try to) use PTRACE_EVENTMSG_SYSCALL_ENTRY/EXIT ?
> >
> > How an application can easily detect whether this feature is implemented?
> 
> As I already said, it can just do ptrace(PTRACE_GET_SYSCALL_INFO, NULL) ?
> If it returns -EIO then this feature is not implemented. Any other error
> code (actually EINVAL or EFAULT) means it is implemented.

Fair enough.
We can change PTRACE_EVENTMSG_SYSCALL_ENTRY/EXIT to 1/2 if you like,
and document this trick somewhere.


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  parent reply	other threads:[~2018-11-30 22:53 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-28 13:04 [PATCH v4 0/2] ptrace: add PTRACE_GET_SYSCALL_INFO request Dmitry V. Levin
     [not found] ` <20181128130439.GB28206-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org>
2018-11-28 13:06   ` [PATCH v4 1/2] ptrace: save the type of syscall-stop in ptrace_message Dmitry V. Levin
2018-11-28 13:49     ` Oleg Nesterov
2018-11-28 14:05       ` Dmitry V. Levin
2018-11-28 14:20         ` Oleg Nesterov
     [not found]           ` <20181128142006.GE30395-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2018-11-28 15:23             ` Dmitry V. Levin
     [not found]               ` <20181128152346.GG28206-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org>
2018-11-28 22:11                 ` Dmitry V. Levin
2018-11-28 23:17                   ` Andy Lutomirski
2018-11-29 10:34                     ` Dmitry V. Levin
2018-11-29 15:03                     ` Oleg Nesterov
2018-11-29 14:47                   ` Oleg Nesterov
     [not found]                     ` <20181129144742.GB10645-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2018-11-29 21:10                       ` Dmitry V. Levin
2018-11-30 11:29                         ` Oleg Nesterov
     [not found]                           ` <20181130112920.GD23670-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2018-11-30 22:53                             ` Dmitry V. Levin [this message]
2018-11-28 13:07 ` [PATCH v4 2/2] ptrace: add PTRACE_GET_SYSCALL_INFO request Dmitry V. Levin
2018-11-28 14:10   ` Oleg Nesterov
2018-11-28 14:29     ` Oleg Nesterov

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