linux-kernel - Re: [PATCH v5] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE

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: <CAADnVQLeCLRhx1Oe5DdJCT0e+WWq4L3Rdee1Ky0JNNh3LdozeQ@mail.gmail.com>
Date: Fri, 9 Jan 2026 13:54:34 -0800
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Steven Rostedt <rostedt@...dmis.org>, LKML <linux-kernel@...r.kernel.org>, 
	Linux trace kernel <linux-trace-kernel@...r.kernel.org>, bpf <bpf@...r.kernel.org>, 
	Masami Hiramatsu <mhiramat@...nel.org>, "Paul E. McKenney" <paulmck@...nel.org>, 
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>, Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v5] tracing: Guard __DECLARE_TRACE() use of
 __DO_TRACE_CALL() with SRCU-fast

On Fri, Jan 9, 2026 at 12:21 PM Mathieu Desnoyers
<mathieu.desnoyers@...icios.com> wrote:
>
>
> * preempt disable/enable pair:                                     1.1 ns
> * srcu-fast lock/unlock:                                           1.5 ns
>
> CONFIG_RCU_REF_SCALE_TEST=y
> * migrate disable/enable pair:                                     3.0 ns

.. and you're arguing that 3ns vs 1ns difference is so important
for your out-of-tree tracer that in-tree tracers need to do
some workarounds?! wtf