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Date: Fri, 7 Jun 2024 11:39:22 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>, mcgrof@kernel.org,
 mhiramat@kernel.org, mark.rutland@arm.com, mathieu.desnoyers@efficios.com,
 jpoimboe@kernel.org, linux-modules@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
 bpf@vger.kernel.org
Subject: Re: [RFC PATCH] ftrace: Skip __fentry__ location of overridden weak
 functions
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In-Reply-To: <20240607150228.GR8774@noisy.programming.kicks-ass.net>
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	<20240607150228.GR8774@noisy.programming.kicks-ass.net>
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On Fri, 7 Jun 2024 17:02:28 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> > There may be following resolutions:  
> 
> Oh gawd, sodding weak functions again.
> 
> I would suggest changing scipts/kallsyms.c to emit readily identifiable
> symbol names for all the weak junk, eg:
> 
>   __weak_junk_NNNNN
> 
> That instantly fixes the immediate problem and Steve's horrid hack can
> go away.

Right. And when I wrote that hack, I specifically said this should be
fixed in kallsyms, and preferably at build time, as that's when the
weak functions should all be resolved.

-- Steve


> 
> Additionally, I would add a boot up pass that would INT3 fill all such
> functions and remove/invalidate all
> static_call/static_jump/fentry/alternative entry that is inside of them.