bug#34235: 27.0.50; lisp profiler does not work

[Alan Mackenzie]

Hello, Alex and Eli.

On Wed, Jan 30, 2019 at 09:40:02 -0600, Alex Branham wrote:

> On Wed 30 Jan 2019 at 07:33, Alan Mackenzie <acm@muc.de> wrote:

> > For what it's worth, I see the bug in master in GNU/Linux, starting off
> > with emacs -Q, visiting xdisp.c, M-x profiler-start <CR> <CR>, M->, M-x
> > profiler-report.

> > I see in the report just the single entry for Automatic GC, like Alex.

> > I last updated my repository yesterday, just before midday UTC.

> Thanks, Alan. Good to know it's not just me.

> Since submitting this bug, I've discovered that it affects previous
> versions of Emacs as well. Emacs from git master that I compile myself,
> Emacs 26.1 from my distro (nixOS), and Emacs 25.3 from my distro. I
> haven't had time yet to dig in much more than that, but figured I'd
> report that as well since it rules out the pdumper.

It seems to be a Linux problem, at least at my end.

I see the bug with kernel versions 4.19.17 and 4.19.13.
I don't see the bug with versions 4.18.19 and 4.19.10.

It seems some incompatibility between Emacs and Linux was introduced in
one of the kernels 4.19.1[123].

I don't know how to debug this any further.

> Alex

-- 
Alan Mackenzie (Nuremberg, Germany).