Re: printk: what is going on with additional newlines?

From: Steven Rostedt
Date: Tue Aug 29 2017 - 21:10:55 EST


On Wed, 30 Aug 2017 10:03:48 +0900
Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> wrote:

> Hello,
>
> On (08/29/17 19:50), Steven Rostedt wrote:
> [..]
> > > A private buffer has none of those issues.
> >
> > What about using the seq_buf*() then?
> >
> > struct seq_buf s;
> >
> > buf = kmalloc(mysize);
> > seq_buf_init(&s, buf, mysize);
> >
> > seq_printf(&s,"blah blah %d", bah_blah);
> > [...]
> > seq_printf(&s, "my last print\n");
> >
> > printk("%.*s", s.len, s.buffer);
> >
> > kfree(buf);
>
> could do. for a single continuation line printk("%.*s", s.len, s.buffer)
> this will work perfectly fine. for a more general case - backtraces, dumps,
> etc. - this requires some tweaks.

We could simply add a seq_buf_printk() that is implemented in the printk
proper, to parse the seq_buf buffer properly, and add the timestamps and
such.

-- Steve