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Date:   Thu, 10 Mar 2022 09:37:31 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Alexei Starovoitov <alexei.starovoitov@gmail.com>, x86@kernel.org,
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Subject: Re: [PATCH v4 00/45] x86: Kernel IBT
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On Thu, 10 Mar 2022 14:47:18 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index acb50fb7ed2d..2d86d3c09d64 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -5354,6 +5381,11 @@ int modify_ftrace_direct(unsigned long ip,
>  	mutex_lock(&direct_mutex);
>  
>  	mutex_lock(&ftrace_lock);
> +
> +	ip = ftrace_location(ip);
> +	if (!ip)
> +		goto out_unlock;
> +

Perhaps this should go into find_direct_entry() instead, as I think you are
adding it before all the find_direct_entry() callers.

And find_direct_entry will update the ip.

-- Steve

>  	entry = find_direct_entry(&ip, &rec);
>  	if (!entry)
>  		goto out_unlock;