Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 10 Oct 2019 11:20:54 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org,
        bristot@redhat.com, jbaron@akamai.com,
        torvalds@linux-foundation.org, tglx@linutronix.de,
        mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org,
        ard.biesheuvel@linaro.org, jpoimboe@redhat.com
Subject: Re: [PATCH v3 5/6] x86/ftrace: Use text_poke()
Message-ID: <20191010092054.GR2311@hirez.programming.kicks-ass.net>
References: <20191007081716.07616230.8@infradead.org>
 <20191007081945.10951536.8@infradead.org>
 <20191008104335.6fcd78c9@gandalf.local.home>
 <20191009224135.2dcf7767@oasis.local.home>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20191009224135.2dcf7767@oasis.local.home>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Oct 09, 2019 at 10:41:35PM -0400, Steven Rostedt wrote:
> On Tue, 8 Oct 2019 10:43:35 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> 
> > BTW, I'd really like to take this patch series through my tree. That
> > way I can really hammer it, as well as I have code that will be built
> > on top of it.
> 
> I did a bit of hammering and found two bugs. One I sent a patch to fix
> (adding a module when tracing is enabled), but the other bug I
> triggered, I'm too tired to debug right now. But figured I'd mention it
> anyway.

I'm thinking this should fix it... Just not sure this is the right plce,
then again, we're doing the same thing in jump_label and static_call, so
perhaps we should do it like this.

--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1230,10 +1230,15 @@ void text_poke_queue(void *addr, const v
  * dynamically allocated memory. This function should be used when it is
  * not possible to allocate memory.
  */
-void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate)
+void __ref text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate)
 {
 	struct text_poke_loc tp;
 
+	if (unlikely(system_state == SYSTEM_BOOTING)) {
+		text_poke_early(addr, opcode, len);
+		return;
+	}
+
 	text_poke_loc_init(&tp, addr, opcode, len, emulate);
 	text_poke_bp_batch(&tp, 1);
 }