linux-kernel - Re: ftrace global trace_pipe

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] [day] [month] [year] [list]

Date:   Wed, 16 Jan 2019 08:47:02 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Claudio <claudio.fontana@...wa.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: Re: ftrace global trace_pipe_raw

On Wed, 16 Jan 2019 09:00:00 +0100
Claudio <claudio.fontana@...wa.com> wrote:

> Indeed the perf event interface would be awesome, if only it would support tracing all processes.
> 
> Unfortunately for my use case, it can only trace one process on any cpus, or all processes on one (1) cpu.
> 
> I guess for some kind of security concerns..

Not security, but performance.

Serialized writes are best done on serialized instances (per cpu or a
single task). Having all tasks on all CPUs write to a single location
is a huge detriment to performance, and has a significant impact. Which
is why the buffer you are asking for doesn't exist.

-- Steve


> 
> I'll take a look at how much work it would be to extend the interface for the any process/any cpu use case.
> 
> Ciao and thank you,
> 
> Claudio
> 
>