Re: [PATCH v2] tty: 8250: fix a missing check for pci_ioremap_bar

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Aditya Pakki <pakki001@umn.edu>
Cc: Kangjie Lu <kjlu@umn.edu>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>, Vinod Koul <vkoul@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	"open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] tty: 8250: fix a missing check for pci_ioremap_bar
Date: Sun, 24 Mar 2019 14:31:11 +0200	[thread overview]
Message-ID: <CAHp75VeyL-G9i=ABg8r6R7+oBBYRDM82L2-jFEm1uK0-136aMw@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VfbPue803w06GdJwU_JYcFKEcShLpyGRMhOg9xi4ZwpAA@mail.gmail.com>

On Sun, Mar 24, 2019 at 2:26 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Sun, Mar 24, 2019 at 2:05 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Sun, Mar 24, 2019 at 12:55 AM Aditya Pakki <pakki001@umn.edu> wrote:
> > >
> > > pci_ioremap_bar could fail. The fix captures the failure and
> > > pass an error code upstream. This can avoid potential NULL
> > > pointer dereferences in the future.
> > >
> >
> > NAK.
> > This will break non-DMA case.
>
> > > @@ -172,12 +172,14 @@ static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
>
> Just to clarify, what you need is simple
>

> void __iomem *regs;

Sorry for leftover.

> chip->pdata = ... //move it here for better looking code
> chip->irq = ...

> chip->regs = pci_ioremap_bar(...);

And looking into the code it needs pci_iounmap() on exit one.

> if (!chip->regs)
>   return;
>
> and thank you for pointing to this.

-- 
With Best Regards,
Andy Shevchenko