linux-kernel - Re: [PATCH v3 1/1] kprobes: retry blocked optprobe in do_free_cleaned

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Message-Id: <20260120145036.f3fda6f57da8fd21745af7e9@kernel.org>
Date: Tue, 20 Jan 2026 14:50:36 +0900
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
To: hongao <hongao@...ontech.com>
Cc: naveen@...nel.org, anil.s.keshavamurthy@...el.com, davem@...emloft.net,
 linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/1] kprobes: retry blocked optprobe in
 do_free_cleaned_kprobes

On Thu, 15 Jan 2026 10:38:03 +0800
hongao <hongao@...ontech.com> wrote:

> Once the aggrprobe is fully reverted in do_free_cleaned_kprobes(), retry
> optimize_kprobe() on that sibling so it can return to OPTIMIZED.
> 
> Also remove the stale comment in __disarm_kprobe().
> 

Thanks, let me pick it.

> Signed-off-by: hongao <hongao@...ontech.com>
> ---
>  kernel/kprobes.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index ab8f9fc1f0d1..1bd84d3b4817 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -516,6 +516,7 @@ static LIST_HEAD(freeing_list);
>  
>  static void kprobe_optimizer(struct work_struct *work);
>  static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
> +static void optimize_kprobe(struct kprobe *p);
>  #define OPTIMIZE_DELAY 5
>  
>  /*
> @@ -593,6 +594,17 @@ static void do_free_cleaned_kprobes(void)
>  			 */
>  			continue;
>  		}
> +
> +		/*
> +		 * The aggregator was holding back another probe while it sat on the
> +		 * unoptimizing/freeing lists.  Now that the aggregator has been fully
> +		 * reverted we can safely retry the optimization of that sibling.
> +		 */
> +
> +		struct kprobe *_p = get_optimized_kprobe(op->kp.addr);
> +		if (unlikely(_p))
> +			optimize_kprobe(_p);
> +
>  		free_aggr_kprobe(&op->kp);
>  	}
>  }
> @@ -1002,12 +1014,6 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt)
>  		if (unlikely(_p) && reopt)
>  			optimize_kprobe(_p);
>  	}
> -	/*
> -	 * TODO: Since unoptimization and real disarming will be done by
> -	 * the worker thread, we can not check whether another probe are
> -	 * unoptimized because of this probe here. It should be re-optimized
> -	 * by the worker thread.
> -	 */
>  }
>  
>  #else /* !CONFIG_OPTPROBES */
> -- 
> 2.50.1
> 


-- 
Masami Hiramatsu (Google) <mhiramat@...nel.org>