From: Thomas Gleixner <tglx@linutronix.de>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
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: Fri, 28 Jun 2019 01:25:13 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1906280124170.32342@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190627231952.nqkbtcculvo2ddif@treble>
On Thu, 27 Jun 2019, Josh Poimboeuf wrote:
> On Fri, Jun 28, 2019 at 01:09:08AM +0200, Thomas Gleixner wrote:
> > On Thu, 27 Jun 2019, Steven Rostedt wrote:
> > > I agree with Josh on this. As the original bug was the race between
> > > ftrace and live patching / modules changing the text from ro to rw and
> > > vice versa. Just protecting the update to the text permissions is more
> > > robust, and should be more self documenting when we need to handle
> > > other architectures for this.
> >
> > How is that supposed to work?
> >
> > ftrace
> > prepare()
> > setrw()
> > setro()
> > patch <- FAIL
>
> /me dodges frozen shark
>
> You are right of course. My brain has apparently already shut off for
> the day.
>
> Maybe a comment or two would help though.
Agreed. That would indeed be useful.
Thanks,
tglx
next prev parent reply other threads:[~2019-06-27 23:25 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 [this message]
2019-06-27 23:25 ` Steven Rostedt
2019-06-28 1:13 ` Steven Rostedt
2019-06-28 1:17 ` Josh Poimboeuf
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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