From: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Helge Deller <deller@gmx.de>,
linux-parisc@vger.kernel.org,
James Bottomley <James.Bottomley@hansenpartnership.com>,
John David Anglin <dave.anglin@bell.net>
Subject: Re: [PATCH] parisc: ftrace: get_kprobe() must be called with preempt disabled
Date: Thu, 5 Nov 2020 21:43:46 -0500 [thread overview]
Message-ID: <20201105214346.2d142cfc@oasis.local.home> (raw)
In-Reply-To: <20201106111758.8b4d6d0197acec6ca4be9a2c@kernel.org>
On Fri, 6 Nov 2020 11:17:58 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> On Tue, 3 Nov 2020 08:42:44 +0100
> Helge Deller <deller@gmx.de> wrote:
>
> > As noticed by Masami Hiramatsu, get_kprobe() must be called with preempt
> > disabled.
>
> Doesn't parisc ftrace implementation preempt off? Then it is required.
>
> Steve, can we expect that op->func() is called under preempt off always
> on any arch or is it arch dependent?
>
Currently all kprobe function callbacks are called with preempt
disabled, because it doesn't have the RECURSIVE_SAFE flag set. And for
callbacks without that set, it goes through a helper function that
disables preemption. My current patch set (which is not upstreamed yet)
is changing that, and I just posted a new patch series that does the
preempt disable before the get_kprobe() function for parsic and other
archs, to handle the new code.
Thus, parsic is currently OK (without my new patch set, it's called
with preemption disabled).
-- Steve
next prev parent reply other threads:[~2020-11-06 2:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-03 7:42 [PATCH] parisc: ftrace: get_kprobe() must be called with preempt disabled Helge Deller
2020-11-06 2:17 ` Masami Hiramatsu
2020-11-06 2:43 ` Steven Rostedt [this message]
2020-11-06 9:03 ` Helge Deller
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