From: Oleg Nesterov <oleg@redhat.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, x86@kernel.org,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
David Laight <David.Laight@aculab.com>
Subject: Re: [RFC PATCH 0/8] uprobe/x86: Add support to optimize prologue
Date: Mon, 8 Dec 2025 11:29:09 +0100 [thread overview]
Message-ID: <aTaodcF1ACgQneRT@redhat.com> (raw)
In-Reply-To: <20251208153056.3a4e9cd3511ccf00dc12e265@kernel.org>
On 12/08, Masami Hiramatsu wrote:
>
> On Mon, 24 Nov 2025 19:12:42 +0100
> Oleg Nesterov <oleg@redhat.com> wrote:
>
> > On 11/17, Jiri Olsa wrote:
> > >
> > > There's an additional issue that single instruction replacement does
> > > not have and it's the possibility of the user space code to jump in the
> > > middle of those 5 bytes. I think it's unlikely to happen at the function
> > > prologue, but uprobe could be placed anywhere. I'm not sure how to
> > > mitigate this other than having some enable/disable switch or config
> > > option, which is unfortunate.
> >
> > plus this breaks single-stepping... Although perhaps we don't really care.
>
> Yeah, and I think we can stop optimization if post_handler is set.
Hmm, why? This doesn't depend on whether ->ret_handler is set or not...
Oleg.
next prev parent reply other threads:[~2025-12-08 10:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-17 12:40 [RFC PATCH 0/8] uprobe/x86: Add support to optimize prologue Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 1/8] uprobe/x86: Introduce struct arch_uprobe_xol object Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 2/8] uprobe/x86: Use struct arch_uprobe_xol in emulate callback Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 3/8] uprobe/x86: Add support to emulate mov reg,reg instructions Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 4/8] uprobe/x86: Add support to emulate sub imm,reg instructions Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 5/8] uprobe/x86: Add support to optimize on top of emulated instructions Jiri Olsa
2025-11-24 18:01 ` Oleg Nesterov
2025-11-26 7:54 ` Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 6/8] selftests/bpf: Add test for mov and sub emulation Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 7/8] selftests/bpf: Add test for uprobe prologue optimization Jiri Olsa
2025-11-17 12:40 ` [RFC PATCH 8/8] selftests/bpf: Add race test for uprobe proglog optimization Jiri Olsa
2025-11-24 18:12 ` [RFC PATCH 0/8] uprobe/x86: Add support to optimize prologue Oleg Nesterov
2025-12-08 6:30 ` Masami Hiramatsu
2025-12-08 10:29 ` Oleg Nesterov [this message]
2025-12-07 22:23 ` Jiri Olsa
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