linux-kernel - Re: [PATCH] uprobe: Move arch_uprobe_optimize right after handlers execution

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAEf4BzYMDgo2JQEkV7e6rnX1Jwu4QMFdqEsnRcxL2J0ukLxU=Q@mail.gmail.com>
Date: Wed, 1 Oct 2025 09:39:27 -0700
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Jiri Olsa <jolsa@...nel.org>
Cc: Oleg Nesterov <oleg@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
	Andrii Nakryiko <andrii@...nel.org>, Linus Torvalds <torvalds@...ux-foundation.org>, bpf@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org, 
	x86@...nel.org, Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>, 
	John Fastabend <john.fastabend@...il.com>, Hao Luo <haoluo@...gle.com>, 
	Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu <mhiramat@...nel.org>, 
	Alan Maguire <alan.maguire@...cle.com>, David Laight <David.Laight@...lab.com>, 
	Thomas Weißschuh <thomas@...ch.de>, 
	Ingo Molnar <mingo@...nel.org>, Jann Horn <jannh@...gle.com>, Alejandro Colomar <alx@...nel.org>
Subject: Re: [PATCH] uprobe: Move arch_uprobe_optimize right after handlers execution

On Wed, Oct 1, 2025 at 6:25 AM Jiri Olsa <jolsa@...nel.org> wrote:
>
> It's less confusing to optimize uprobe right after handlers execution
> and before we do the check for changed ip register to avoid situations
> where changed ip register would skip uprobe optimization.
>
> Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  kernel/events/uprobes.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>

makes sense

Acked-by: Andrii Nakryiko <andrii@...nel.org>

> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 5dcf927310fd..c14ec27b976d 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -2765,6 +2765,9 @@ static void handle_swbp(struct pt_regs *regs)
>
>         handler_chain(uprobe, regs);
>
> +       /* Try to optimize after first hit. */
> +       arch_uprobe_optimize(&uprobe->arch, bp_vaddr);
> +
>         /*
>          * If user decided to take execution elsewhere, it makes little sense
>          * to execute the original instruction, so let's skip it.
> @@ -2772,9 +2775,6 @@ static void handle_swbp(struct pt_regs *regs)
>         if (instruction_pointer(regs) != bp_vaddr)
>                 goto out;
>
> -       /* Try to optimize after first hit. */
> -       arch_uprobe_optimize(&uprobe->arch, bp_vaddr);
> -
>         if (arch_uprobe_skip_sstep(&uprobe->arch, regs))
>                 goto out;
>
> --
> 2.51.0
>