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From: Peter Zijlstra <peterz@infradead.org>
To: Petr Pavlu <petr.pavlu@suse.com>
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, hpa@zytor.com, mhiramat@kernel.org,
	samitolvanen@google.com, x86@kernel.org,
	linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] x86/retpoline,kprobes: Avoid treating rethunk as an indirect jump
Date: Wed, 5 Jul 2023 10:58:57 +0200	[thread overview]
Message-ID: <20230705085857.GG462772@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20230705081547.25130-3-petr.pavlu@suse.com>

On Wed, Jul 05, 2023 at 10:15:47AM +0200, Petr Pavlu wrote:
> Functions can_optimize() and insn_is_indirect_jump() consider jumps to
> the range [__indirect_thunk_start, __indirect_thunk_end] as indirect
> jumps and prevent use of optprobes in functions containing them.

Why ?!? I mean, doing an opt-probe of an indirect jump/call instruction
itself doesn't really make sense and I can see why you'd want to not do
that. But why disallow an opt-probe if there's one in the function as a
whole, but not the probe target?

  reply	other threads:[~2023-07-05  9:01 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-05  8:15 [PATCH 0/2] x86/retpoline,kprobes: Fix the [__indirect_thunk_start, ..end] range Petr Pavlu
2023-07-05  8:15 ` [PATCH 1/2] x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG Petr Pavlu
2023-07-05  8:52   ` Peter Zijlstra
2023-07-05  8:15 ` [PATCH 2/2] x86/retpoline,kprobes: Avoid treating rethunk as an indirect jump Petr Pavlu
2023-07-05  8:58   ` Peter Zijlstra [this message]
2023-07-05 14:20     ` Masami Hiramatsu
2023-07-05 14:50       ` Peter Zijlstra
2023-07-06  0:47         ` Masami Hiramatsu
2023-07-06  7:17           ` Peter Zijlstra
2023-07-06  9:00             ` Masami Hiramatsu
2023-07-06 11:34               ` Peter Zijlstra
2023-07-07 14:39                 ` Masami Hiramatsu
2023-07-08 14:18                 ` Petr Pavlu
2023-07-09 15:25                   ` Masami Hiramatsu
2023-07-05  9:02   ` Peter Zijlstra
2023-07-05 14:40   ` Masami Hiramatsu

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