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From: Andrew Lunn <andrew@lunn.ch>
To: Josh Coombs <josh.coombs@gmail.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
	linux ARM <linux-arm-kernel@lists.infradead.org>,
	wlanfae@realtek.com, Larry.Finger@lwfinger.net,
	florian.c.schilhabel@googlemail.com, gregkh@linuxfoundation.org,
	devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
	Andrew Lunn <andrew@lunn.ch>
Subject: Re: [Patch v1 1/1] RTL8712 alignment bug in 3.6.5 on ARM
Date: Sun, 18 Nov 2012 19:20:49 +0100	[thread overview]
Message-ID: <20121118182049.GE14643@lunn.ch> (raw)
In-Reply-To: <CAMW5Ufb9D+BYGtZUWPBWKMtk11QMpR1N+2Q1yb4w_GdvV17p+w@mail.gmail.com>

> >> diff -ruN a/drivers/staging/rtl8712/rtl871x_sta_mgt.c
> >> b/drivers/staging/rtl8712/rtl871x_sta_mgt.c
> >> --- a/drivers/staging/rtl8712/rtl871x_sta_mgt.c 2012-11-05
> >> 03:57:06.000000000 -0500
> >> +++ b/drivers/staging/rtl8712/rtl871x_sta_mgt.c 2012-11-13
> >> 12:54:28.000000000 -0500
> >> @@ -55,8 +55,8 @@
> >>     NUM_STA + 4);
> >>   if (pstapriv->pallocated_stainfo_buf == NULL)
> >>   return _FAIL;
> >> - pstapriv->pstainfo_buf = pstapriv->pallocated_stainfo_buf + 4 -
> >> - ((addr_t)(pstapriv->pallocated_stainfo_buf) & 3);
> >> + pstapriv->pstainfo_buf = pstapriv->pallocated_stainfo_buf + 8 -
> >> + ((addr_t)(pstapriv->pallocated_stainfo_buf) & 7);
> >
> > Are you sure this is safe?  Is the allocated buffer large enough for
> > those additional 4 bytes of alignment you're adding?
> 
> I'm not certain on that, I bumped the allocations at Andrew's
> suggestion, but don't know enough to certify the changes as 100%
> correct.

Its not correct.

The original code is:

        pstapriv->pallocated_stainfo_buf = _malloc(sizeof(struct sta_info) *
                                                   NUM_STA + 4);
        if (pstapriv->pallocated_stainfo_buf == NULL)
                return _FAIL;
        pstapriv->pstainfo_buf = pstapriv->pallocated_stainfo_buf + 4 -
                ((addr_t)(pstapriv->pallocated_stainfo_buf) & 3);

The 4 in the _malloc() also needs increasing to 8.

    Andrew

WARNING: multiple messages have this Message-ID (diff)
From: andrew@lunn.ch (Andrew Lunn)
To: linux-arm-kernel@lists.infradead.org
Subject: [Patch v1 1/1] RTL8712 alignment bug in 3.6.5 on ARM
Date: Sun, 18 Nov 2012 19:20:49 +0100	[thread overview]
Message-ID: <20121118182049.GE14643@lunn.ch> (raw)
In-Reply-To: <CAMW5Ufb9D+BYGtZUWPBWKMtk11QMpR1N+2Q1yb4w_GdvV17p+w@mail.gmail.com>

> >> diff -ruN a/drivers/staging/rtl8712/rtl871x_sta_mgt.c
> >> b/drivers/staging/rtl8712/rtl871x_sta_mgt.c
> >> --- a/drivers/staging/rtl8712/rtl871x_sta_mgt.c 2012-11-05
> >> 03:57:06.000000000 -0500
> >> +++ b/drivers/staging/rtl8712/rtl871x_sta_mgt.c 2012-11-13
> >> 12:54:28.000000000 -0500
> >> @@ -55,8 +55,8 @@
> >>     NUM_STA + 4);
> >>   if (pstapriv->pallocated_stainfo_buf == NULL)
> >>   return _FAIL;
> >> - pstapriv->pstainfo_buf = pstapriv->pallocated_stainfo_buf + 4 -
> >> - ((addr_t)(pstapriv->pallocated_stainfo_buf) & 3);
> >> + pstapriv->pstainfo_buf = pstapriv->pallocated_stainfo_buf + 8 -
> >> + ((addr_t)(pstapriv->pallocated_stainfo_buf) & 7);
> >
> > Are you sure this is safe?  Is the allocated buffer large enough for
> > those additional 4 bytes of alignment you're adding?
> 
> I'm not certain on that, I bumped the allocations at Andrew's
> suggestion, but don't know enough to certify the changes as 100%
> correct.

Its not correct.

The original code is:

        pstapriv->pallocated_stainfo_buf = _malloc(sizeof(struct sta_info) *
                                                   NUM_STA + 4);
        if (pstapriv->pallocated_stainfo_buf == NULL)
                return _FAIL;
        pstapriv->pstainfo_buf = pstapriv->pallocated_stainfo_buf + 4 -
                ((addr_t)(pstapriv->pallocated_stainfo_buf) & 3);

The 4 in the _malloc() also needs increasing to 8.

    Andrew

  reply	other threads:[~2012-11-18 18:22 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-18 17:06 [Patch v1 1/1] RTL8712 alignment bug in 3.6.5 on ARM Josh Coombs
2012-11-18 17:06 ` Josh Coombs
2012-11-18 17:47 ` Russell King - ARM Linux
2012-11-18 17:47   ` Russell King - ARM Linux
2012-11-18 18:03   ` Josh Coombs
2012-11-18 18:03     ` Josh Coombs
2012-11-18 18:20     ` Andrew Lunn [this message]
2012-11-18 18:20       ` Andrew Lunn
2012-11-18 20:10       ` Josh Coombs
2012-11-18 20:10         ` Josh Coombs
2012-11-19  3:37       ` Josh Coombs
2012-11-19  3:37         ` Josh Coombs
2012-11-18 18:11 ` Andrew Lunn
2012-11-18 18:11   ` Andrew Lunn
2012-11-18 20:18   ` Larry Finger
2012-11-18 20:18     ` Larry Finger
2012-11-18 20:55     ` Andrew Lunn
2012-11-18 20:55       ` Andrew Lunn
2012-11-19  0:10       ` Larry Finger
2012-11-19  0:10         ` Larry Finger

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