From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suman Anna Subject: Re: [PATCHv2 02/16] iommu/omap: omap_iommu_attach() should return ENODEV, not NULL Date: Wed, 26 Feb 2014 10:45:02 -0600 Message-ID: <530E1A0E.4020609@ti.com> References: <1392315347-32967-1-git-send-email-s-anna@ti.com> <2290716.T9AJoGfoRd@avalon> <530D19E3.9030407@ti.com> <18584919.CMGx44dZjC@avalon> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <18584919.CMGx44dZjC@avalon> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Laurent Pinchart Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tony Lindgren , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Florian Vaussard List-Id: linux-omap@vger.kernel.org Hi Laurent, > On Tuesday 25 February 2014 16:32:03 Suman Anna wrote: >> On 02/25/2014 03:13 PM, Laurent Pinchart wrote: >>> On Thursday 13 February 2014 12:15:33 Suman Anna wrote: >>>> From: Florian Vaussard >>>> >>>> omap_iommu_attach() returns NULL or ERR_PTR in case of error, but >>>> omap_iommu_attach_dev() only checks for IS_ERR. Thus a NULL return value >>>> (in case driver_find_device fails) will cause the kernel to panic when >>>> omap_iommu_attach_dev() dereferences the pointer. >>>> >>>> In such case, omap_iommu_attach() should return ENODEV, not NULL. >>>> >>>> Signed-off-by: Florian Vaussard >>>> Acked-by: Suman Anna >>>> --- >>>> >>>> drivers/iommu/omap-iommu.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c >>>> index fff2ffd..6272c36 100644 >>>> --- a/drivers/iommu/omap-iommu.c >>>> +++ b/drivers/iommu/omap-iommu.c >>>> @@ -863,7 +863,7 @@ static int device_match_by_alias(struct device *dev, >>>> void *data) **/ >>>> >>>> static struct omap_iommu *omap_iommu_attach(const char *name, u32 >>>> *iopgd) >>>> { >>>> - int err = -ENOMEM; >>>> + int err = -ENODEV; >>>> struct device *dev; >>>> struct omap_iommu *obj; >>>> >>>> @@ -871,7 +871,7 @@ static struct omap_iommu *omap_iommu_attach(const >>>> char *name, u32 *iopgd) >>>> (void *)name, >>>> device_match_by_alias); >>>> if (!dev) >>>> - return NULL; >>>> + return ERR_PTR(err); >>> >>> I would return ERR_PTR(-ENODEV) here, and remove the initialization at >>> declaration of err above. >> >> The initialization at the beginning is also serving one another exit >> path (a check for try_module_get), where err is not being set. If the >> initialization is removed, then the err has to be set explicitly at the >> other place. Let me know if you still want this changed. > > The return value of iommu_enable() is unconditionally stored in err before the > try_module_get() call, so that code patch is buggy anyway and should be fixed. > I would still remove the initialization at declaration and assign -ENODEV to > err explicitly when try_module_get() fails before the goto err_module. OK, I will fix this up. regards Suman