From: Thomas Gleixner <tglx@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Josh Poimboeuf <jpoimboe@redhat.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 00:17:56 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1906280017000.32342@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190627081334.12793-1-pmladek@suse.com>
On Thu, 27 Jun 2019, Petr Mladek wrote:
> Fortunately, the problematic fix is needed only on x86_64. It is
> the only architecture that calls set_all_modules_text_rw()
> in ftrace path and supports livepatching at the same time.
>
> Therefore it is enough to move text_mutex handling from the generic
> kernel/trace/ftrace.c into arch/x86/kernel/ftrace.c:
>
> ftrace_arch_code_modify_prepare()
> ftrace_arch_code_modify_post_process()
>
> This patch basically reverts the ftrace part of the problematic
^^^^^^^^^ Sigh
> commit 9f255b632bf12c4dd7 ("module: Fix livepatch/ftrace module
> text permissions race"). And provides x86_64 specific-fix.
>
> Some refactoring of the ftrace code will be needed when livepatching
> is implemented for arm or nds32. These architectures call
> set_all_modules_text_rw() and use stop_machine() at the same time.
>
> Fixes: 9f255b632bf12c4dd7 ("module: Fix livepatch/ftrace module text permissions race")
> Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
next prev parent reply other threads:[~2019-06-27 22:18 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 [this message]
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
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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