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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Mon, 5 Jul 2021 10:04:41 +0200
From:   Ingo Molnar <mingo@kernel.org>
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>, X86 ML <x86@kernel.org>,
        Daniel Xu <dxu@dxuuu.xyz>, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com,
        ast@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        Peter Zijlstra <peterz@infradead.org>, kernel-team@fb.com,
        yhs@fb.com, linux-ia64@vger.kernel.org,
        Abhishek Sagar <sagar.abhishek@gmail.com>,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>
Subject: Re: [PATCH -tip v8 08/13] arm: kprobes: Make a space for
 regs->ARM_pc at kretprobe_trampoline
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* Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Change kretprobe_trampoline to make a space for regs->ARM_pc so that
> kretprobe_trampoline_handler can call instruction_pointer_set()
> safely.

The idiom is "make space", but in any case, what does this mean?

Was the stack frame set up in kretprobe_trampoline() and calling 
trampoline_handler() buggy?

If yes, then explain the bad effects of the bug, and make all of this clear 
in the title & changelog.

Thanks,

	Ingo