From: Steven Rostedt <rostedt@goodmis.org>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: David Laight <david.laight.linux@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
mingo@redhat.com, will@kernel.org, boqun@kernel.org,
longman@redhat.com, mhiramat@kernel.org, mark.rutland@arm.com,
mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [RFC PATCH 1/2] locking: add mutex_lock_nospin()
Date: Wed, 4 Mar 2026 22:00:19 -0500 [thread overview]
Message-ID: <20260304220019.3efa12ab@robin> (raw)
In-Reply-To: <CALOAHbBA643_QOsnTmrfjKE71hSa+v1cToiELvGk+vjtcgJsxg@mail.gmail.com>
On Thu, 5 Mar 2026 10:33:00 +0800
Yafang Shao <laoar.shao@gmail.com> wrote:
> Other tools may also read available_filter_functions, requiring each
> one to be patched individually to avoid this flaw—a clearly
> impractical solution.
What exactly is the issue? If a task does a while 1 in user space, it
wouldn't be much different. With PREEMPT_LAZY the most a task will spin
in the kernel is one extra tick over a user space task spinning in user
space.
available_filter_functions is definitely not a hot path, so I
personally don't care if it were to use "nospin". My worry is about
adding this "special" mutex for a single corner case, and I want to know
that its a real bug before we add something special into the kernel.
-- Steve
next prev parent reply other threads:[~2026-03-05 3:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-04 7:46 [RFC PATCH 0/2] disable optimistic spinning for ftrace_lock Yafang Shao
2026-03-04 7:46 ` [RFC PATCH 1/2] locking: add mutex_lock_nospin() Yafang Shao
2026-03-04 9:02 ` Peter Zijlstra
2026-03-04 9:37 ` Yafang Shao
2026-03-04 10:11 ` Peter Zijlstra
2026-03-04 11:52 ` Yafang Shao
2026-03-04 12:41 ` Peter Zijlstra
2026-03-04 14:25 ` Yafang Shao
2026-03-04 9:54 ` David Laight
2026-03-04 20:57 ` Steven Rostedt
2026-03-04 21:44 ` David Laight
2026-03-05 2:17 ` Yafang Shao
2026-03-05 2:28 ` Steven Rostedt
2026-03-05 2:33 ` Yafang Shao
2026-03-05 3:00 ` Steven Rostedt [this message]
2026-03-05 3:08 ` Yafang Shao
2026-03-05 4:30 ` Waiman Long
2026-03-05 5:40 ` Yafang Shao
2026-03-05 13:21 ` Steven Rostedt
2026-03-06 2:22 ` Yafang Shao
2026-03-06 10:00 ` David Laight
2026-03-09 2:34 ` Yafang Shao
2026-03-05 18:34 ` Waiman Long
2026-03-05 18:44 ` Waiman Long
2026-03-06 2:27 ` Yafang Shao
2026-03-05 9:32 ` David Laight
2026-03-05 19:00 ` Waiman Long
2026-03-06 2:33 ` Yafang Shao
2026-03-06 18:12 ` kernel test robot
2026-03-06 18:24 ` kernel test robot
2026-03-04 7:46 ` [RFC PATCH 2/2] ftrace: disable optimistic spinning for ftrace_lock Yafang Shao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260304220019.3efa12ab@robin \
--to=rostedt@goodmis.org \
--cc=boqun@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=david.laight.linux@gmail.com \
--cc=laoar.shao@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=longman@redhat.com \
--cc=mark.rutland@arm.com \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.