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Tue, 15 Aug 2023 12:13:46 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 3sepmjm64h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 15 Aug 2023 12:13:46 +0000 Received: from smtpav07.fra02v.mail.ibm.com (smtpav07.fra02v.mail.ibm.com [10.20.54.106]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 37FCDh6f44040734 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 15 Aug 2023 12:13:43 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 97E7420043; Tue, 15 Aug 2023 12:13:43 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5B6AC2004B; Tue, 15 Aug 2023 12:13:43 +0000 (GMT) Received: from osiris (unknown [9.152.212.60]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTPS; Tue, 15 Aug 2023 12:13:43 +0000 (GMT) Date: Tue, 15 Aug 2023 14:13:41 +0200 From: Heiko Carstens To: Ruan Jinjie Cc: linux-s390@vger.kernel.org, Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle Subject: Re: [PATCH -next] s390/hmcdrv: Switch to memdup_user_nul() helper Message-ID: <20230815121341.18151-A-hca@linux.ibm.com> References: <20230815115546.1604722-1-ruanjinjie@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230815115546.1604722-1-ruanjinjie@huawei.com> X-TM-AS-GCONF: 00 X-Proofpoint-GUID: LhGvJ5ZY5ZY5HQi1cCNZGj79m2Ie04Sp X-Proofpoint-ORIG-GUID: LhGvJ5ZY5ZY5HQi1cCNZGj79m2Ie04Sp X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-08-15_10,2023-08-15_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1011 impostorscore=0 adultscore=0 bulkscore=0 suspectscore=0 malwarescore=0 mlxscore=0 phishscore=0 mlxlogscore=553 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2306200000 definitions=main-2308150108 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Tue, Aug 15, 2023 at 07:55:46PM +0800, Ruan Jinjie wrote: > Use memdup_user_nul() helper instead of open-coding > to simplify the code. > > Signed-off-by: Ruan Jinjie > --- > drivers/s390/char/hmcdrv_dev.c | 17 +++++------------ > 1 file changed, 5 insertions(+), 12 deletions(-) > > diff --git a/drivers/s390/char/hmcdrv_dev.c b/drivers/s390/char/hmcdrv_dev.c > index 8d50c894711f..504cdbf9998d 100644 > --- a/drivers/s390/char/hmcdrv_dev.c > +++ b/drivers/s390/char/hmcdrv_dev.c > @@ -252,19 +252,12 @@ static ssize_t hmcdrv_dev_write(struct file *fp, const char __user *ubuf, > fp, (long long) *pos, len); > > if (!fp->private_data) { /* first expect a cmd write */ > - fp->private_data = kmalloc(len + 1, GFP_KERNEL); > - > - if (!fp->private_data) > - return -ENOMEM; > - > - if (!copy_from_user(fp->private_data, ubuf, len)) { > - ((char *)fp->private_data)[len] = '\0'; > - return len; > + fp->private_data = memdup_user_nul(ubuf, len); > + if (IS_ERR(fp->private_data)) { > + fp->private_data = NULL; > + return PTR_ERR(fp->private_data); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This is obviously broken. Sorry, but I'm not willing to review such "trivial" cleanup patches for subtle bugs anymore - maybe you would sooner or later succeed and I would apply such a broken patch. Just don't send such patches; at least I won't take them.