From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH 1/6] i2c: omap: Prevent NULL pointer dereference in remove Date: Sat, 18 Aug 2012 12:09:23 +0200 Message-ID: <20120818100923.GD24812@pengutronix.de> References: <1344519467-14295-1-git-send-email-shubhrajyoti@ti.com> <1344519467-14295-2-git-send-email-shubhrajyoti@ti.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bajzpZikUji1w+G9" Return-path: Content-Disposition: inline In-Reply-To: <1344519467-14295-2-git-send-email-shubhrajyoti-l0cyMroinI0@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Shubhrajyoti D Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org --bajzpZikUji1w+G9 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Aug 09, 2012 at 07:07:42PM +0530, Shubhrajyoti D wrote: > Prevent the NULL pointer access by moving the platform_set_drvdata functi= on > after the access of the pdev. >=20 > [ 654.961761] Unable to handle kernel NULL pointer dereference at virtua= l address 00000070 > [ 654.970611] pgd =3D df254000 > [ 654.973480] [00000070] *pgd=3D9f1da831, *pte=3D00000000, *ppte=3D00000= 000 > [ 654.980163] Internal error: Oops: 17 [#1] SMP ARM > [ 654.985076] Modules linked in: > [ 654.988281] CPU: 1 Not tainted (3.6.0-rc1-00031-ge547de1-dirty #33= 9) > [ 654.995330] PC is at omap_i2c_runtime_resume+0x8/0x148 > [ 655.000732] LR is at omap_i2c_runtime_resume+0x8/0x148 >=20 > Signed-off-by: Shubhrajyoti D > --- > drivers/i2c/busses/i2c-omap.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) >=20 > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index c8e3886..0c593d4 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -1217,8 +1217,6 @@ static int __devexit omap_i2c_remove(struct platfor= m_device *pdev) > struct omap_i2c_dev *dev =3D platform_get_drvdata(pdev); > int ret; > =20 > - platform_set_drvdata(pdev, NULL); > - > i2c_del_adapter(&dev->adapter); > ret =3D pm_runtime_get_sync(&pdev->dev); > if (IS_ERR_VALUE(ret)) > @@ -1227,6 +1225,8 @@ static int __devexit omap_i2c_remove(struct platfor= m_device *pdev) > omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0); > pm_runtime_put(&pdev->dev); > pm_runtime_disable(&pdev->dev); > + platform_set_drvdata(pdev, NULL); > + > return 0; > } I think this patch is correct, because drvdata is used in the PM code of the driver and thus cleared too early. As such, this is a bugfix and should be not based on the big cleanup since it should go into this rc series. I will pick it as soon as the comments on the other patches are answered. --=20 Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ | --bajzpZikUji1w+G9 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAlAvadMACgkQD27XaX1/VRtiiwCgjtwwFbrh8jY4YaZRXVwfvycx NmUAn0ssWmtMxSJM/KFuMo9MwlYo3UJ1 =ppae -----END PGP SIGNATURE----- --bajzpZikUji1w+G9--