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From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Sami Tolvanen <samitolvanen@google.com>,
	kernel test robot <oliver.sang@intel.com>,
	Kees Cook <keescook@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	lkp@lists.01.org, kernel test robot <lkp@intel.com>
Subject: Re: [x86, build] 6dafca9780: WARNING:at_arch/x86/kernel/ftrace.c:#ftrace_verify_code
Date: Tue, 2 Mar 2021 10:19:47 +0100	[thread overview]
Message-ID: <YD4DM6uAETid7j4l@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210301201526.65ce7f1c@oasis.local.home>

On Mon, Mar 01, 2021 at 08:15:26PM -0500, Steven Rostedt wrote:
> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index 7edbd5ee5ed4..e8afc765e00a 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -36,6 +36,7 @@
>  #ifdef CONFIG_DYNAMIC_FTRACE
>  
>  static int ftrace_poke_late = 0;
> +static const char p6_nop[] = { P6_NOP5 };

I don't understand this approach, why not simply rewrite all the nops at
boot and not worry about it when modifying the code later?

WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: lkp@lists.01.org
Subject: Re: [x86, build] 6dafca9780: WARNING:at_arch/x86/kernel/ftrace.c:#ftrace_verify_code
Date: Tue, 02 Mar 2021 10:19:47 +0100	[thread overview]
Message-ID: <YD4DM6uAETid7j4l@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210301201526.65ce7f1c@oasis.local.home>

[-- Attachment #1: Type: text/plain, Size: 520 bytes --]

On Mon, Mar 01, 2021 at 08:15:26PM -0500, Steven Rostedt wrote:
> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index 7edbd5ee5ed4..e8afc765e00a 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -36,6 +36,7 @@
>  #ifdef CONFIG_DYNAMIC_FTRACE
>  
>  static int ftrace_poke_late = 0;
> +static const char p6_nop[] = { P6_NOP5 };

I don't understand this approach, why not simply rewrite all the nops at
boot and not worry about it when modifying the code later?

  parent reply	other threads:[~2021-03-02  9:49 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-01  7:40 [x86, build] 6dafca9780: WARNING:at_arch/x86/kernel/ftrace.c:#ftrace_verify_code kernel test robot
2021-03-01  7:40 ` kernel test robot
2021-03-01 22:14 ` Sami Tolvanen
2021-03-01 22:14   ` Sami Tolvanen
2021-03-01 23:45   ` Steven Rostedt
2021-03-01 23:45     ` Steven Rostedt
2021-03-02  0:03     ` Sami Tolvanen
2021-03-02  0:03       ` Sami Tolvanen
2021-03-02  1:15       ` Steven Rostedt
2021-03-02  1:15         ` Steven Rostedt
2021-03-02  2:40         ` Sami Tolvanen
2021-03-02  2:40           ` Sami Tolvanen
2021-03-02  2:47           ` Steven Rostedt
2021-03-02  2:47             ` Steven Rostedt
2021-03-02  3:23             ` Sami Tolvanen
2021-03-02  3:23               ` Sami Tolvanen
2021-03-02  9:19         ` Peter Zijlstra [this message]
2021-03-02  9:19           ` Peter Zijlstra
2021-03-02 15:58           ` Steven Rostedt
2021-03-02 15:58             ` Steven Rostedt

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