Re: [PATCH v2] parport: register driver later

[Greg KH]

On Tue, Apr 05, 2016 at 06:26:08AM +0100, Sudip Mukherjee wrote:
> On Mon, Mar 07, 2016 at 10:32:55AM -0700, Ross Zwisler wrote:
> > On Sun, Mar 06, 2016 at 08:40:10PM +0530, Sudip Mukherjee wrote:
> > > If the parport bus is not yet registered and any device using parallel
> > > port tries to register with the bus we get a stackdump with a message
> > > of Kernel bug.
> > > 
> > > Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
> > > Cc: <stable@xxxxxxxxxxxxxxx> # 4.2+
> > > Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
> > > ---
> > > 
> > > Hi Ross,
> > > Can you please test this patch in your setup. This is a respin of the
> > > previous patch in another way.
> > 
> > Yep, this also solves the issue for me.
> > 
> > Tested-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> 
> Hi Greg,
> If this patch is ok, can we please have it in v4.6 .
> Anyway, the problem patch which this patch tried to fix has already
> been reverted by Linus - 
> 1701f680407c ("Revert "ppdev: use new parport device model"") but we still
> can have problem with the other devices that use parport.
> 
> BTW, I know you are busy, but in these situations where I need to have
> the fix urgently in the tree, is there any other way to solve the purpose?
> I feel it was incompetency on my part where Linus had to interfere and
> revert a patch even though the fix was already posted.

A bit better commit message here would have caused me to notice it.
Something like "Revert a broken patch because it crashes all of our
machines without it!!!" would be a hint it needed to go in :)

I think the lack of parport hardware around seems to have caused a total
lack of testing this code path while it was in linux-next and in my
local testing, sorry about that, it should have been caught a lot
earlier.

thanks,

greg k-h