Re: [PATCH 4.19 185/306] net: hns3: bugfix for buffer not free problem during resetting

[Greg Kroah-Hartman]

On Fri, Nov 29, 2019 at 11:24:01PM +0100, Pavel Machek wrote:
> Hi!
> 
> > > > From: Huazhong Tan <tanhuazhong@xxxxxxxxxx>
> > > > 
> > > > [ Upstream commit 73b907a083b8a8c1c62cb494bc9fbe6ae086c460 ]
> > > > 
> > > > When hns3_get_ring_config()/hns3_queue_to_ring()/
> > > > hns3_get_vector_ring_chain() failed during resetting, the allocated
> > > > memory has not been freed before these three functions return. So
> > > > this patch adds error handler in these functions to fix it.
> > > 
> > > Correct me if I'm wrong, but... this introduces use-after-free:
> > > Should it do devm_kfree(&pdev->dev, cur_chain); ?
> > 
> > I think Sasha tried to backport a fix for this patch, but that fix broke
> > the build :(
> > 
> > If you want to provide a working backport, I'll be glad to take it.
> 
> Actually it looks like problem originated in mainline, and there was
> more than one problem with this patch.
> 
> cda69d244585bc4497d3bb878c22fe2b6ad647c1 should fix it; it needs to be
> back-ported, too.

Yes, that is the one, can you provide a working backport for this?

thanks,

greg k-h