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From:   Yafang Shao <laoar.shao@gmail.com>
Date:   Thu, 22 Nov 2018 21:29:52 +0800
Message-ID: <CALOAHbBaR2GB1Xtzzi9bNprfCWSP_PV5FCfAG_xK=jqg8uuong@mail.gmail.com>
Subject: Re: [PATCH] procfs: fix the output format in /proc/PID/wchan
To:     Alexey Dobriyan <adobriyan@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>, viro@zeniv.linux.org.uk,
        Kees Cook <keescook@chromium.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org
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On Thu, Nov 22, 2018 at 7:40 PM Alexey Dobriyan <adobriyan@gmail.com> wrote:
>
> On Wed, Nov 21, 2018 at 07:28:44PM -0800, Andrew Morton wrote:
> > On Mon, 19 Nov 2018 19:17:52 +0800 Yafang Shao <laoar.shao@gmail.com> wrote:
> >
> > > Just add the missing newline.
> > >
> > > ...
> > >
> > > --- a/fs/proc/base.c
> > > +++ b/fs/proc/base.c
> > > @@ -370,11 +370,12 @@ static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
> > >     wchan = get_wchan(task);
> > >     if (wchan && !lookup_symbol_name(wchan, symname)) {
> > >             seq_puts(m, symname);
> > > +           seq_putc(m, '\n');
> > >             return 0;
> > >     }
> > >
> > >  print0:
> > > -   seq_putc(m, '0');
> > > +   seq_puts(m, "0\n");
> > >     return 0;
> > >  }
> > >  #endif /* CONFIG_KALLSYMS */
> >
> > What is presently wrong with the wchan output?  The changelog
> > should explain such things, please.
>
> It is just newline to make "cat /proc/*/wchan" output look cool.
> But newline can break something.

Could you pls. show some examples for what the newline may break ?

Thanks
Yafang