Re: [PATCH 00/25] tty: serial: drop uart_port->lock before calling

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Aug 16, 2013 at 05:13:01PM +0530, Viresh Kumar wrote:
> The -rt patch triggers a lockdep warning for serial drivers if
> tty_flip_buffer_push() is called with uart_port->lock locked. This never shows
> up on UP kernels.

What about SMP kernels?  linux-next?

> Release the port lock before calling tty_flip_buffer_push() and reacquire it
> after the call.
> 
> Similar stuff was already done for few other drivers in the past, like:
> 
> commit 2389b272168ceec056ca1d8a870a97fa9c26e11a
> Author: Thomas Gleixner <tglx@linutronix.de>
> Date:   Tue May 29 21:53:50 2007 +0100
> 
>     [ARM] 4417/1: Serial: Fix AMBA drivers locking
> 
> This is neither tested nor compiled.

So I'm guessing you don't want it to be applied, if you can't take the
time to at least test-build it, why should we?

{sigh}

> I was working on Samsung's Arndale board
> and so was required to samsung serial driver. Then thought why not others :)
> 
> Rebased over: v3.11-rc5

Lots of tty and serial changes have happened since -rc5 in linux-next,
can you please rebase, and test, these against that tree and resend them
if they are still needed?

thanks,

greg k-h