linux-kernel - Re: [PATCH 1/2] tracepoints: Add helper to test if tracepoint is enabled in a header

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200925111415.60f5334c@oasis.local.home>
Date:   Fri, 25 Sep 2020 11:14:15 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc:     paulmck <paulmck@...nel.org>,
        Michael Jeanson <mjeanson@...icios.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Yafang Shao <laoar.shao@...il.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Michel Lespinasse <walken@...gle.com>,
        Daniel Jordan <daniel.m.jordan@...cle.com>,
        Davidlohr Bueso <dbueso@...e.de>,
        linux-mm <linux-mm@...ck.org>, Ingo Molnar <mingo@...nel.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: Re: [PATCH 1/2] tracepoints: Add helper to test if tracepoint is
 enabled in a header

On Fri, 25 Sep 2020 10:41:56 -0400 (EDT)
Mathieu Desnoyers <mathieu.desnoyers@...icios.com> wrote:

> With the current dependencies of tracepoint.h, I would argue that we should
> only do the trampoline work-around for cases where there is an unavoidable
> circular dependency, like the case of msr.h. For other headers which don't
> have circular dependency issues with tracepoint.h, we should use the usual
> tracepoint instrumentation because not having the trampoline provides better
> tracing (on) speed and reduces (slightly) code size.

Well, for now, I'm going to add the helper function and have the header
use cases use that.

A while back ago I had patches that moves the DO_TRACE() work into a
separate function and with that we probably could have let all
tracepoints be in headers (as they would all just do a function call to
the trace algorithm that does the rest of the work). But you balked at
that because of the added overhead with tracing on.

Anyway, I don't see any issues with the current patch set as is
(besides the documentation fix, which I already updated locally). And
will add this to my queue for linux-next.

-- Steve