From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754496AbaIVRvg (ORCPT ); Mon, 22 Sep 2014 13:51:36 -0400 Received: from mail-ob0-f171.google.com ([209.85.214.171]:39570 "EHLO mail-ob0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754020AbaIVRvf (ORCPT ); Mon, 22 Sep 2014 13:51:35 -0400 From: Ashley Lai X-Google-Original-From: Ashley Lai Date: Mon, 22 Sep 2014 12:45:38 -0500 (CDT) To: Anton Blanchard cc: Peter Huewe , Ashley Lai , Marcel Selhorst , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] tpm/tpm_ibmvtpm: Fail in ibmvtpm_get_data if driver_data is bad In-Reply-To: <20140920072942.27c28768@kryten> Message-ID: References: <20140920072942.27c28768@kryten> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 20 Sep 2014, Anton Blanchard wrote: > I'm looking at an oops in tpm_ibmvtpm_get_desired_dma: > > 28: 00 00 20 39 li r9,0 > 2c: 10 00 01 e8 ld r0,16(r1) > 30: 28 00 69 80 lwz r3,40(r9) > > We set r9 to 0 then load r9+40. The problem is actually in > ibmvtpm_get_data, it can return NULL but the rest of the driver > never expects it. > > Add a BUG_ON in ibmvtpm_get_data. We still need to identify the root > cause but at least this makes it obvious what went wrong. > > Cc: stable@vger.kernel.org > Signed-off-by: Anton Blanchard > --- > > diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c > index af74c57..0d1eeba 100644 > --- a/drivers/char/tpm/tpm_ibmvtpm.c > +++ b/drivers/char/tpm/tpm_ibmvtpm.c > @@ -63,9 +63,9 @@ static int ibmvtpm_send_crq(struct vio_dev *vdev, u64 w1, u64 w2) > static struct ibmvtpm_dev *ibmvtpm_get_data(const struct device *dev) > { > struct tpm_chip *chip = dev_get_drvdata(dev); > - if (chip) > - return (struct ibmvtpm_dev *)TPM_VPRIV(chip); > - return NULL; > + > + BUG_ON(!chip); > + return (struct ibmvtpm_dev *)TPM_VPRIV(chip); > } > > /** > Acked-by: Ashley Lai