Re: [PATCH v2 1/4] tracing: Fix checking of freed trace_event_file for hist files

[Steven Rostedt]

On Mon, 16 Feb 2026 14:41:57 +0100
Petr Pavlu <petr.pavlu@xxxxxxxx> wrote:

> diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
> index 3690221ba3d8..f925034e402d 100644
> --- a/include/linux/trace_events.h
> +++ b/include/linux/trace_events.h
> @@ -683,6 +683,11 @@ static inline void hist_poll_wakeup(void)
>  
>  #define hist_poll_wait(file, wait)	\
>  	poll_wait(file, &hist_poll_wq, wait)
> +
> +#else
> +static inline void hist_poll_wakeup(void)
> +{
> +}
>  #endif
>  
>  #define __TRACE_EVENT_FLAGS(name, value)				\
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index 137b4d9bb116..e8ed6ba155cf 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -1295,6 +1295,9 @@ static void remove_event_file_dir(struct trace_event_file *file)
>  	free_event_filter(file->filter);
>  	file->flags |= EVENT_FILE_FL_FREED;
>  	event_file_put(file);
> +
> +	/* Wake up hist poll waiters to notice the EVENT_FILE_FL_FREED flag. */
> +	hist_poll_wakeup();
>  }
>  
>  /*
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index c97bb2fda5c0..744c2aa3d668 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -5778,7 +5778,7 @@ static __poll_t event_hist_poll(struct file *file, struct poll_table_struct *wai
>  
>  	guard(mutex)(&event_mutex);
>  
> -	event_file = event_file_data(file);
> +	event_file = event_file_file(file);
>  	if (!event_file)
>  		return EPOLLERR;
>  
> @@ -5816,7 +5816,7 @@ static int event_hist_open(struct inode *inode, struct file *file)
>  
>  	guard(mutex)(&event_mutex);
>  
> -	event_file = event_file_data(file);
> +	event_file = event_file_file(file);
>  	if (!event_file) {
>  		ret = -ENODEV;
>  		goto err;
> -- 

This should be broken into two different patches. One for the
hist_poll_wakeup() fix, the other to use event_file_file().

-- Steve