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

[Steven Rostedt]

On Tue, 17 Feb 2026 10:29:57 -0500
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> 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

Replying with my kernel.org account in case this email ended up in your spam folder.

-- Steve