From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Petr Mladek <pmladek@suse.com>, Miroslav Benes <mbenes@suse.cz>,
Jessica Yu <jeyu@kernel.org>, Jiri Kosina <jikos@kernel.org>,
Joe Lawrence <joe.lawrence@redhat.com>,
linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
Johannes Erdfelt <johannes@erdfelt.com>,
Ingo Molnar <mingo@kernel.org>,
mhiramat@kernel.org, torvalds@linux-foundation.org
Subject: Re: [PATCH] ftrace: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()
Date: Thu, 27 Jun 2019 20:17:25 -0500 [thread overview]
Message-ID: <20190628011725.rctv3chdlqwkfwcx@treble> (raw)
In-Reply-To: <20190627211304.7e21fd77@gandalf.local.home>
On Thu, Jun 27, 2019 at 09:13:04PM -0400, Steven Rostedt wrote:
> On Thu, 27 Jun 2019 18:19:52 -0500
> Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
>
> > Maybe a comment or two would help though.
> >
>
> I'm adding the following change. Care to add a "reviewed-by" for this
> one?
>
> -- Steve
>
> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index 33786044d5ac..d7e93b2783fd 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -36,6 +36,11 @@
>
> int ftrace_arch_code_modify_prepare(void)
> {
> + /*
> + * Need to grab text_mutex to prevent a race from module loading
> + * and live kernel patching from changing the text permissions while
> + * ftrace has it set to "read/write".
> + */
> mutex_lock(&text_mutex);
> set_kernel_text_rw();
> set_all_modules_text_rw();
For the patch+comment:
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
next prev parent reply other threads:[~2019-06-28 1:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 8:13 [PATCH] ftrace: Remove possible deadlock between register_kprobe() and ftrace_run_update_code() Petr Mladek
2019-06-27 22:17 ` Thomas Gleixner
2019-06-27 22:47 ` Josh Poimboeuf
2019-06-27 23:04 ` Steven Rostedt
2019-06-27 23:09 ` Thomas Gleixner
2019-06-27 23:12 ` Steven Rostedt
2019-06-27 23:19 ` Josh Poimboeuf
2019-06-27 23:25 ` Thomas Gleixner
2019-06-27 23:25 ` Steven Rostedt
2019-06-28 1:13 ` Steven Rostedt
2019-06-28 1:17 ` Josh Poimboeuf [this message]
2019-06-28 17:33 ` Jiri Kosina
2019-06-28 17:37 ` Steven Rostedt
2019-06-29 20:56 ` Jiri Kosina
2019-06-29 21:19 ` Steven Rostedt
2019-06-29 21:22 ` [PATCH] ftrace/x86: anotate text_mutex split between ftrace_arch_code_modify_post_process() and ftrace_arch_code_modify_prepare() Jiri Kosina
2019-06-28 7:32 ` [PATCH] ftrace: Remove possible deadlock between register_kprobe() and ftrace_run_update_code() Miroslav Benes
2019-06-28 10:52 ` Petr Mladek
2019-06-28 13:54 ` Steven Rostedt
2019-06-28 15:46 ` Steven Rostedt
2019-06-28 15:51 ` Josh Poimboeuf
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