LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Arnd Bergmann <arnd@arndb.de>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	Amitkumar Karwar <amitkarwar@gmail.com>,
	Siva Rebbagondla <siva8118@gmail.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] rsi: Properly initialize data in rsi_sdio_ta_reset
Date: Thu, 23 May 2019 10:51:01 +0200	[thread overview]
Message-ID: <CAK8P3a001V5qQo4vGfpugtmrnFfUNeP_q4KY-YS7rP_L91HY1A@mail.gmail.com> (raw)
In-Reply-To: <20190523015415.GA17819@archlinux-epyc>

On Thu, May 23, 2019 at 3:54 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> On Thu, May 02, 2019 at 08:17:18PM -0700, Nathan Chancellor wrote:
> > On Thu, May 02, 2019 at 11:18:01AM -0700, Nick Desaulniers wrote:
> > > On Thu, May 2, 2019 at 8:16 AM Nathan Chancellor
> > > u8 data [4];
> >
> > data was __le32 in rsi_reset_chip() before commit f700546682a6 ("rsi:
> > fix nommu_map_sg overflow kernel panic").
> >
> > I wonder if this would be okay for this function:
> >
> > -------------------------------------------------
> >
> > diff --git a/drivers/net/wireless/rsi/rsi_91x_sdio.c b/drivers/net/wireless/rsi/rsi_91x_sdio.c
> > index f9c67ed473d1..0330c50ab99c 100644
> > --- a/drivers/net/wireless/rsi/rsi_91x_sdio.c
> > +++ b/drivers/net/wireless/rsi/rsi_91x_sdio.c
> > @@ -927,7 +927,7 @@ static int rsi_sdio_ta_reset(struct rsi_hw *adapter)
> >  {
> >         int status;
> >         u32 addr;
> > -       u8 *data;
> > +       u8 data;
> >
> >         status = rsi_sdio_master_access_msword(adapter, TA_BASE_ADDR);
> >         if (status < 0) {
> > @@ -937,7 +937,7 @@ static int rsi_sdio_ta_reset(struct rsi_hw *adapter)
> >         }
> >
> >         rsi_dbg(INIT_ZONE, "%s: Bring TA out of reset\n", __func__);
> > -       put_unaligned_le32(TA_HOLD_THREAD_VALUE, data);
> > +       put_unaligned_le32(TA_HOLD_THREAD_VALUE, &data);
> >         addr = TA_HOLD_THREAD_REG | RSI_SD_REQUEST_MASTER;
> >         status = rsi_sdio_write_register_multiple(adapter, addr,
> >                                                   (u8 *)&data,

This is clearly not ok, as put_unaligned_le32() stores four bytes, and
the local variable is only one byte!

Also, sdio does use DMA for transfers, so the variable has to be
dynamically allocated. I think your original patch was correct.
The only change I'd possibly make would be to use
RSI_9116_REG_SIZE instead of sizeof(u32).

> Did any of the maintainers have any comments on what the correct
> solution is here to resolve this warning? It is one of the few left
> before we can turn on -Wuninitialized for the whole kernel.

I would argue that this should not stop us from turning it on, as the
warning is for a clear bug in the code that absolutely needs to be
fixed, rather than a false-positive.

       Arnd

  reply	other threads:[~2019-05-23  8:51 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-02 15:15 Nathan Chancellor
2019-05-02 18:18 ` Nick Desaulniers
2019-05-03  3:17   ` Nathan Chancellor
2019-05-23  1:54     ` Nathan Chancellor
2019-05-23  8:51       ` Arnd Bergmann [this message]
2019-05-23  8:56         ` Kalle Valo
2019-05-23  8:52       ` Kalle Valo
2019-05-03  4:38   ` Kalle Valo
2019-05-06 20:51     ` Nathan Chancellor
2019-05-23 15:30 ` [PATCH v2 5.2] " Nathan Chancellor
2019-05-28 11:33   ` Kalle Valo

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=CAK8P3a001V5qQo4vGfpugtmrnFfUNeP_q4KY-YS7rP_L91HY1A@mail.gmail.com \
    --to=arnd@arndb.de \
    --cc=amitkarwar@gmail.com \
    --cc=clang-built-linux@googlegroups.com \
    --cc=kvalo@codeaurora.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=natechancellor@gmail.com \
    --cc=ndesaulniers@google.com \
    --cc=netdev@vger.kernel.org \
    --cc=siva8118@gmail.com \
    --subject='Re: [PATCH] rsi: Properly initialize data in rsi_sdio_ta_reset' \
    /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

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).