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Wed, 23 Sep 2026 14:38:11 +0000 (GMT) Received: from osiris (unknown [9.111.16.152]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 23 Sep 2026 14:38:11 +0000 (GMT) Date: Wed, 23 Sep 2026 16:38:10 +0200 From: Heiko Carstens To: Vineeth Vijayan Cc: oberpar@linux.ibm.com, agordeev@linux.ibm.com, gor@linux.ibm.com, linux-s390@vger.kernel.org Subject: Re: [PATCH] s390/cio: Fix NULL dereference in ccw_device_get_util_str() Message-ID: <20260923143810.9636D86-hca@linux.ibm.com> References: <20260922204839.965043-1-vneethv@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260922204839.965043-1-vneethv@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: U_e5hHroj89nsmZi67NP7tRXI9BnaLE8 X-Authority-Analysis: v=2.4 cv=EOCTQFZC c=1 sm=1 tr=0 ts=6ab3e458 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=8nJEP1OIZ-IA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=IIzHxe9DFIFphaoEM7oA:9 a=3ZKOabzyN94A:10 a=wPNLvfGTeEIA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTIzMDA1OCBTYWx0ZWRfXzUt3ymT7ZaXN J9RHMDcSNGhkKLfMl33Nxhsv7XSErt1OG9m0WDwotyld3VGPkZavA38+6WGn5dsM+Eb/VRoXjKh 10J+SjTyYvW6NlE+bqlz3F70mhNWXCU= X-Proofpoint-GUID: U_e5hHroj89nsmZi67NP7tRXI9BnaLE8 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTIzMDA1OCBTYWx0ZWRfX4l2ndCGKRziv J3dsvMorpUcJvQ5pNKFHlTuvMQ/CcQsH7u5BfgDllhpQmHDgK6fes/uVeo/NWmiwccJ9fwwA2DR RMeXi9gPU1metYxz4X8ZX5A9XDw0TInw8N8fX/bgnd9fGPpQ4rMXdjo8z+rekKlRolJh2moJ9fs NIPfehrk/mkLGRjlN2RJ0jEaN04dv6IqYkOA+oqyTogFGTKzAZq42Bf7cErsLNWms0ELhL/L/6p e8Cia69QN0clPhDLuteWPEpcOxZWVwIhRM/0roC0eHbq2Zec8+VlSiFTJmB1CZbUFoXSQhRD4Kz imKIxgp3aqtEjDstEloLBudz0i109i+kfCg6IDHgbjJzRJBqV4V9vvoY19pfLhu7dMQrBC/ZSF9 5/DjW/uRbznAPpBQnaRYHmMWdM5VIEOpoV6SQiwtIro4Zb5h24wWH3g8JfzsymzVyW5HSGKh89d sqBrmye8+dUna5dDZBQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-23_04,2026-09-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 phishscore=0 priorityscore=1501 clxscore=1015 spamscore=0 adultscore=0 impostorscore=0 lowpriorityscore=0 suspectscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609230058 On Tue, Sep 22, 2026 at 10:48:39PM +0200, Vineeth Vijayan wrote: > The channel path registry entry associated with a CHPID may be removed > while the subchannel's PMCW still references that CHPID. In this case, > chpid_to_chp() can return NULL, leading to a NULL pointer dereference. >   > Add the missing NULL check before dereferencing the returned pointer. > + if (!chp) > + return NULL; > > util_str = kmalloc(sizeof(chp->desc_fmt3.util_str), GFP_KERNEL); The context diff is confusing; as if this would be the to be fixed bug :) But ok, just a few lines below chp is indeed dereferenced. Applied, thanks!