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: <20260111170953.49127c00@fedora>
Date: Sun, 11 Jan 2026 17:09:53 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, 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 Sun, 11 Jan 2026 12:04:51 -0800
Alexei Starovoitov <alexei.starovoitov@...il.com> wrote:

> The diff has nothing to do with bpf needs and/or bpf internals.
> It's really about being a good citizen of PREEMP_RT.
> bpf side already does migrate_disable,
> rcu_read_lock, srcu_fast/task_trace when necessary.
> Most of the time we don't rely on any external preempt state or rcu/srcu.
> Removing guard(preempt_notrace)(); from tracepoint invocation
> would be just fine for bpf. Simple remove will trigger bug
> on cant_sleep(), but that's a trivial fix.

Oh, so you are OK replacing the preempt_disable in the tracepoint
callbacks with fast SRCU? 

Then I guess we can simply do that. Would it be fine to do that for
both RT and non-RT? That will simplify the code quite a bit.

-- Steve