Re: [PATCH 1/4] tracing: add run-time field descriptions for eventfiltering

[Steven Rostedt]

On Sun, 22 Mar 2009, Frederic Weisbecker wrote:
> >  static DEFINE_MUTEX(event_mutex);
> >  
> > +int trace_define_field(struct ftrace_event_call *call, char *type,
> > +		       char *name, int offset, int size)
> > +{
> > +	struct ftrace_event_field *field;
> > +
> > +	field = kmalloc(sizeof(*field), GFP_KERNEL);
> > +	if (!field)
> > +		goto err;
> > +	field->name = kstrdup(name, GFP_KERNEL);
> > +	if (!field->name)
> > +		goto err;
> > +	field->type = kstrdup(type, GFP_KERNEL);
> > +	if (!field->type)
> > +		goto err;
> > +	field->offset = offset;
> > +	field->size = size;
> > +	list_add(&field->link, &call->fields);
> > +
> > +	return 0;
> > +err:
> > +	if (field) {
> > +		kfree(field->name);
> > +		kfree(field->type);
> 
> 
> You need kzalloc to allocate field.
> With kmalloc, field will point to random filled memory
> after a fresh allocation.
> 
> Imagine this path:
> 
> if (!field->name)
> 	goto err;
> ...
> err:
> 	kfree(field->name) <- field->name = NULL, correct
> 	kfree(field->type) <- field->type = ?
> 

Looks like Frederic got to you first ;-)

-- Steve

> 
> > +	}
> > +	kfree(field);
> > +	return -ENOMEM;
> > +}
> > +
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