Re: [PATCH v3] crypto: AF_ALG - remove locking in async callback

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Fri, 24 Nov 2017 17:04:19 +0100
Stephan Mueller <smueller@chronox.de> wrote:

> Am Freitag, 24. November 2017, 08:37:39 CET schrieb Herbert Xu:
> 
> Hi Herbert,
> 
> > On Fri, Nov 10, 2017 at 01:20:55PM +0100, Stephan Müller wrote:  
> > > The code paths protected by the socket-lock do not use or modify the
> > > socket in a non-atomic fashion. The actions pertaining the socket do not
> > > even need to be handled as an atomic operation. Thus, the socket-lock
> > > can be safely ignored.
> > > 
> > > This fixes a bug regarding scheduling in atomic as the callback function
> > > may be invoked in interrupt context.
> > > 
> > > In addition, the sock_hold is moved before the AIO encrypt/decrypt
> > > operation to ensure that the socket is always present. This avoids a
> > > tiny race window where the socket is unprotected and yet used by the AIO
> > > operation.
> > > 
> > > Finally, the release of resources for a crypto operation is moved into a
> > > common function of af_alg_free_resources.
> > > 
> > > Fixes: e870456d8e7c8 ("crypto: algif_skcipher - overhaul memory
> > > management") Fixes: d887c52d6ae43 ("crypto: algif_aead - overhaul memory
> > > management") Reported-by: Romain Izard <romain.izard.pro@gmail.com>
> > > Signed-off-by: Stephan Mueller <smueller@chronox.de>  
> > 
> > Patch applied.  Thanks.  
> 
> Thanks a lot.
> 
> Would it make sense to feed it to stable?
> 
> Ciao
> Stephan
My view would be definitely.  Ran into this precise issue whilst testing
a new driver 4.14 today...

Jonathan