Re: [Qemu-trivial] [Qemu-devel] [PATCH] gdbstub: avoid busy loop while waiting for gdb

[Peter Wu <peter@lekensteyn.nl>]

On Thu, May 05, 2016 at 04:37:40PM +0100, Peter Maydell wrote:
> On 3 May 2016 at 23:58, Peter Wu <peter@lekensteyn.nl> wrote:
> > While waiting for a gdb response, or while sending an acknowledgement
> > there is not much to do, so just mark the socket as non-blocking to
> > avoid a busy loop while paused at gdb. This only affects the user-mode
> > emulation (qemu-arm -g 1234 ./a.out).
> >
> > Note that this issue was reported before at
> > https://lists.nongnu.org/archive/html/qemu-devel/2013-02/msg02277.html.
> >
> > While at it, close the gdb client fd on EOF or error while reading.
> 
> The commit message says "mark the socket as non-blocking"...
> 
> > @@ -1599,8 +1603,6 @@ static void gdb_accept(void)
> >      gdb_has_xml = false;
> >
> >      gdbserver_state = s;
> > -
> > -    fcntl(fd, F_SETFL, O_NONBLOCK);
> >  }
> 
> ...but the code change is *removing* a call to mark the
> socket as non-blocking. Which is correct?
> 
> thanks
> -- PMM

The commit message is misleading, it should have been "so do not mark
the socket as non-blocking". If you were to apply this, please fix it up
:-)
-- 
Kind regards,
Peter Wu
https://lekensteyn.nl