From: Oleg Nesterov <oleg@redhat.com>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@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, 24 Nov 2025 19:12:42 +0100 [thread overview]
Message-ID: <aSSgGu8X04XoYN8D@redhat.com> (raw)
In-Reply-To: <20251117124057.687384-1-jolsa@kernel.org>
On 11/17, Jiri Olsa wrote:
>
> This patchset adds support to optimize uprobe on top of instruction
> that could be emulated and also adds support to emulate particular
> versions of mov and sub instructions to cover some of the user space
> functions prologues, like:
>
> pushq %rbp
> movq %rsp,%rbp
> subq $0xb0,%rsp
...
> 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.
Oleg.
next prev parent reply other threads:[~2025-11-24 18:12 UTC|newest]
Thread overview: 16+ 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
2025-11-20 11:50 ` kernel test robot
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 ` Oleg Nesterov [this message]
2025-12-08 6:30 ` [RFC PATCH 0/8] uprobe/x86: Add support to optimize prologue Masami Hiramatsu
2025-12-08 10:29 ` Oleg Nesterov
2025-12-07 22:23 ` Jiri Olsa
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