Re: [PATCH] tracing: skip boot kprobe setup when no events were requested

[Masami Hiramatsu (Google)]

On Fri,  6 Nov 2026 10:14:57 +0800, Wenwen Fu <wenwfu@xxxxxxxxxxxxxxxx> wrote:
> setup_boot_kprobe_events() calls enable_boot_kprobe_events() even when
> the kprobe_event= boot parameter was not supplied. That call takes
> event_mutex without any command-line probes to enable.
> 
> Asynchronous eval-map updates also hold event_mutex. A normal boot can
> therefore wait in init_kprobe_trace() for this background work despite
> having no boot probes to set up.
> 
> Return early when the boot-event buffer is empty. Keep the mutex
> protection in trace_event_update_all() and retain setup for explicit
> kprobe_event= parameters. Bootconfig handles its own probe enablement,
> and the existing trace_eval_sync() still waits for background work
> before init memory is freed.

Nice catch! This looks good to me. Let me pick it with below tag.

Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter")

Thanks,

> 
> Signed-off-by: Wenwen Fu <wenwfu@xxxxxxxxxxxxxxxx>
> ---
>  kernel/trace/trace_kprobe.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index ee8171b19bee..52ec16d8d838 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1995,6 +1995,9 @@ static __init void setup_boot_kprobe_events(void)
>  	char *p, *cmd = kprobe_boot_events_buf;
>  	int ret;
>  
> +	if (!kprobe_boot_events_buf[0])
> +		return;
> +
>  	strreplace(kprobe_boot_events_buf, ',', ' ');
>  
>  	while (cmd && *cmd != '\0') {
>

-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>