Re: [PATCH] Add Linux PTRACE_EVENT_STOP

[Kir Kolyshkin <kir at openvz dot org>]

On 02/07/2017 12:32 AM, Dmitry V. Levin wrote:
> On Tue, Feb 07, 2017 at 12:06:05AM -0800, Kir Kolyshkin wrote:
> > Add PTRACE_EVENT_STOP value to Linux's sys/ptrace.h, modify related
> > comments accordingly.
> >
> > This constant initially appeared in Linux 3.1 (kernel commit 3544d72a,
> > "ptrace: implement PTRACE_SEIZE") but its value has changed later
> > in Linux 3.4 (kernel commit 5cdf389a, "ptrace: renumber
> > PTRACE_EVENT_STOP so that future new options and events can match").
> >
> > The comment is also taken from the above commit.
> >
> > This constant is used by e.g. strace, CRIU, Mozilla RR.
> JFTR, strace has a workaround for this early PTRACE_EVENT_STOP bug:
>
> #ifdef PTRACE_EVENT_STOP
> /* Linux 3.1 - 3.3 releases had a broken value.  It was fixed in 3.4.  */
> # if PTRACE_EVENT_STOP == 7
> #  undef PTRACE_EVENT_STOP
> # endif
> #endif
> #ifndef PTRACE_EVENT_STOP
> # define PTRACE_EVENT_STOP      128
> #endif

In CRIU, we just define it to a correct value (and do not include 
linux/ptrace.h
as there can be conflicts between sys/ptrace.h and kernel/ptrace.h; in fact
there is one in musl libc).

Would be good for glibc headers to provide the value though.

> > 2017-02-06  Kir Kolyshkin  <kir@openvz.org>
> >
> > 	* sysdeps/unix/sysv/linux/aarch64/sys/ptrace.h: Add PTRACE_EVENT_STOP.
> It should rather be
>
> 	* sysdeps/unix/sysv/linux/aarch64/sys/ptrace.h (__ptrace_eventcodes):
> 	Add PTRACE_EVENT_STOP.

Thanks! I can send v2, but am not sure if I should, as it is minor
and the patch is already ack'ed.

> > 	* sysdeps/unix/sysv/linux/ia64/sys/ptrace.h: Likewise.
> > 	* sysdeps/unix/sysv/linux/powerpc/sys/ptrace.h: Likewise.
> > 	* sysdeps/unix/sysv/linux/s390/sys/ptrace.h: Likewise.
> > 	* sysdeps/unix/sysv/linux/sparc/sys/ptrace.h: Likewise.
> > 	* sysdeps/unix/sysv/linux/sys/ptrace.h: Likewise.
> > 	* sysdeps/unix/sysv/linux/tile/sys/ptrace.h: Likewise.
> The whole change LGTM.