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From: Oleg Nesterov <oleg@redhat.com>
To: Liao Chang <liaochang1@huawei.com>
Cc: mhiramat@kernel.org, peterz@infradead.org, mingo@redhat.com,
	acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com,
	alexander.shishkin@linux.intel.com, jolsa@kernel.org,
	irogers@google.com, adrian.hunter@intel.com,
	kan.liang@linux.intel.com, linux-kernel@vger.kernel.org,
	linux-trace-kernel@vger.kernel.org,
	linux-perf-users@vger.kernel.org
Subject: Re: [PATCH] uprobes: Improve scalability by reducing the contention on siglock
Date: Thu, 1 Aug 2024 16:06:39 +0200	[thread overview]
Message-ID: <20240801140639.GE4038@redhat.com> (raw)
In-Reply-To: <20240801082407.1618451-1-liaochang1@huawei.com>

On 08/01, Liao Chang wrote:
>
> @@ -2276,22 +2277,25 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs)
>  	int err = 0;
>  
>  	uprobe = utask->active_uprobe;
> -	if (utask->state == UTASK_SSTEP_ACK)
> +	switch (utask->state) {
> +	case UTASK_SSTEP_ACK:
>  		err = arch_uprobe_post_xol(&uprobe->arch, regs);
> -	else if (utask->state == UTASK_SSTEP_TRAPPED)
> +		break;
> +	case UTASK_SSTEP_TRAPPED:
>  		arch_uprobe_abort_xol(&uprobe->arch, regs);
> -	else
> +		fallthrough;
> +	case UTASK_SSTEP_DENY_SIGNAL:
> +		set_tsk_thread_flag(current, TIF_SIGPENDING);
> +		break;
> +	default:
>  		WARN_ON_ONCE(1);
> +	}

Liao, at first glance this change looks "obviously wrong" to me.

But let me read this patch more carefully and reply on weekend,
I am a bit busy right now.

Thanks,

Oleg.


  reply	other threads:[~2024-08-01 14:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-01  8:24 [PATCH] uprobes: Improve scalability by reducing the contention on siglock Liao Chang
2024-08-01 14:06 ` Oleg Nesterov [this message]
2024-08-02  1:38   ` Liao, Chang
2024-08-02  9:24     ` Oleg Nesterov
2024-08-06  3:06       ` Liao, Chang
2024-08-06 17:25         ` Oleg Nesterov
2024-08-07 10:17           ` Oleg Nesterov
2024-08-08  7:30             ` Liao, Chang
2024-08-08 10:28               ` Oleg Nesterov
2024-08-08 12:31                 ` Liao, Chang
2024-08-08 13:17                   ` Oleg Nesterov

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