From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 19 Mar 2012 11:37:44 +0100 From: Martin Schwidefsky Subject: Re: [PATCH]s390/char/vmur.c: memory leak Fix in the driver Message-ID: <20120319113744.5992d48f@de.ibm.com> In-Reply-To: <491D6B4EAD0A714894D8AD22F4BDE04304FF5A@SCYBEXDAG04.amd.com> References: <491D6B4EAD0A714894D8AD22F4BDE0430495F2@SCYBEXDAG04.amd.com> <491D6B4EAD0A714894D8AD22F4BDE04304FF5A@SCYBEXDAG04.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: "Chen, Dennis (SRDC SW)" Cc: "linux-kernel@vger.kernel.org" , "beattiem@uk.ibm.com" , "holzheu@de.ibm.com" , "munzert@de.ibm.com" , "linux390@de.ibm.com" , "linux-s390@vger.kernel.org" , "heiko.carstens@de.ibm.com" List-ID: On Mon, 19 Mar 2012 01:55:40 +0000 "Chen, Dennis (SRDC SW)" wrote: > CC'ing maintainer: Martin Schwidefsky & Heiko Carstens... > > -----Original Message----- > From: Chen, Dennis (SRDC SW) > Sent: Sunday, March 18, 2012 3:41 AM > To: linux-kernel@vger.kernel.org > Cc: beattiem@uk.ibm.com; holzheu@de.ibm.com; munzert@de.ibm.com; linux390@de.ibm.com; linux-s390@vger.kernel.org; Chen, Dennis (SRDC SW) > Subject: [PATCH]s390/char/vmur.c: memory leak Fix in the driver > > This patch is used to fix a memory leak issue in s390/char/vmur.c: a character device instance is > allocated by cdev_alloc, the cdev_del will not free that space if cdev_init is applied before. > > Signed-off-by: dennis1.chen@amd.com > --- a/s390/char/vmur.c 2012-03-18 02:50:47.950963949 +0800 > +++ b/s390/char/vmur.c 2012-03-18 03:12:04.790936740 +0800 > @@ -903,7 +903,7 @@ static int ur_set_online(struct ccw_devi > goto fail_urdev_put; > } > > - cdev_init(urd->char_device, &ur_fops); > + urd->char_device->ops = &ur_fops; > urd->char_device->dev = MKDEV(major, minor); > urd->char_device->owner = ur_fops.owner; > How does that fix anything? My copy of cdev_init looks like this: void cdev_init(struct cdev *cdev, const struct file_operations *fops) { memset(cdev, 0, sizeof *cdev); INIT_LIST_HEAD(&cdev->list); kobject_init(&cdev->kobj, &ktype_cdev_default); cdev->ops = fops; } It does not allocate anything but it initializes some more fields. The new code would only initialize the ops field. In addition cdev_del does a kobject_put and the release function of the object will call cdev_dynamic_release as far as I can tell. That code should be fine as it is. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.