Re: [PATCH] proc/wchan: Use printk format instead of lookup_symbol_name()

[Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>]

On Wed, 23 Dec 2020 10:48:10 +0100 Helge Deller <deller@xxxxxx> wrote:

> >  static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
> >  			  struct pid *pid, struct task_struct *task)
> >  {
> > -	unsigned long wchan;
> > -
> >  	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
> > -		wchan = get_wchan(task);
> > -	else
> > -		wchan = 0;
> > -
> > -	if (wchan)
> > -		seq_printf(m, "%ps", (void *) wchan);
> > +		seq_printf(m, "%ps", (void *)get_wchan(task));
> >  	else
> >  		seq_putc(m, '0');
> 
> get_wchan() does return NULL sometimes, in which case with
> your change now "0x0" instead of "0" gets printed.

Ah, OK, ignore ;)