linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Ulf Hansson <ulf.hansson@linaro.org>
To: Arnd Bergmann <arnd@kernel.org>, Shawn Lin <shawn.lin@rock-chips.com>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mmc: warn for invalid SDIO data buffers【请注意,邮件由linux-mmc-owner@vger.kernel.org代发】
Date: Fri, 2 Jul 2021 10:19:13 +0200	[thread overview]
Message-ID: <CAPDyKFrbQxyYUpFXfg2t071uN0JcCo74QsJ5Fx-VCkND-KKjPQ@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a3UjLfKpsg2M-RP3AO3CVCnZrbD71uaLf0+iiJ9RJsHCQ@mail.gmail.com>

On Fri, 2 Jul 2021 at 09:03, Arnd Bergmann <arnd@kernel.org> wrote:
>
> On Fri, Jul 2, 2021 at 3:02 AM Shawn Lin <shawn.lin@rock-chips.com> wrote:
> > On 2021/6/30 20:20, Arnd Bergmann wrote:
> > > From: Arnd Bergmann <arnd@arndb.de>
> > >
> > > Jernej Skrabec reported a problem with the cw1200 driver failing on
> > > arm64 systems with CONFIG_VMAP_STACK=y.
> > >
> > > The driver in this case passes a pointer to a stack variable (in vmalloc
> > > space) into the sdio layer, which gets translated into an invalid DMA
> > > address.
> > >
> > > Even without CONFIG_VMAP_STACK, the driver is still unreliable, as
> > > cache invalidations on the DMA buffer may cause random data corruption
> > > in adjacent stack slots.
> > >
> > > This could be worked around in the SDIO core, but in the discussion we
> > > decided that passing a stack variable into SDIO should always be considered
> > > a bug, as it is for USB drivers.
> > >
> > > Change the sdio core to produce a one-time warning for any on-stack
> > > (both with and without CONFIG_VMAP_STACK) as well as any vmalloc
> > > or module-local address that would have the same translation problem.
> >
> > This was the previous comment about the same topic.
> > Should we check for mmc_io_rw_direct?
> >
> > https://www.spinics.net/lists/linux-mmc/msg41794.html
>
> Hi Shawn,
>
> thank you for remembering that previous discussion, that is a
> good question. Looking at the code though, I don't actually
> see any part of mmc_io_rw_direct() doing DMA on a caller-provided
> buffer. The only thing I see in the code is a 'u8 *out' argument, but
> that is just a pointer to a single byte that is set by this function.
>
> Do you see any other issue with that function, or does that mean
> we don't have to change it?

I was wrong when I earlier said that we needed to care about
mmc_io_rw_direct(). mmc_io_rw_direct() transfer "data" over the CMD
line. MMC host drivers can't do DMA on that.

I think the $subject patch looks reasonable to me.

Kind regards
Uffe

      parent reply	other threads:[~2021-07-02  8:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-30 12:20 [PATCH] mmc: warn for invalid SDIO data buffers Arnd Bergmann
2021-06-30 23:02 ` kernel test robot
2021-07-01  9:06   ` Arnd Bergmann
2021-07-02  1:02 ` [PATCH] mmc: warn for invalid SDIO data buffers【请注意,邮件由linux-mmc-owner@vger.kernel.org代发】 Shawn Lin
2021-07-02  7:03   ` Arnd Bergmann
2021-07-02  8:15     ` Shawn Lin
2021-07-02  8:19     ` Ulf Hansson [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAPDyKFrbQxyYUpFXfg2t071uN0JcCo74QsJ5Fx-VCkND-KKjPQ@mail.gmail.com \
    --to=ulf.hansson@linaro.org \
    --cc=adrian.hunter@intel.com \
    --cc=arnd@kernel.org \
    --cc=jernej.skrabec@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mmc@vger.kernel.org \
    --cc=shawn.lin@rock-chips.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).