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Wed, 5 Aug 2026 11:16:16 +0000 (GMT) From: Stefan Haberland To: Jens Axboe Cc: linux-block@vger.kernel.org, Jan Hoeppner , linux-s390@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Christian Borntraeger Subject: [PATCH 03/19] s390/dasd: Guard sysfs discipline callbacks against unallocated private data Date: Wed, 5 Aug 2026 13:15:56 +0200 Message-ID: <20260805111612.1285190-4-sth@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260805111612.1285190-1-sth@linux.ibm.com> References: <20260805111612.1285190-1-sth@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: gjITN24cvWARj90i9WlD-L6L_HKIl-sm X-Proofpoint-ORIG-GUID: gjITN24cvWARj90i9WlD-L6L_HKIl-sm X-Proofpoint-Spam-Info: AW1haW4tMjYwODA1MDA4NiBTYWx0ZWRfX079eEcqHBQUc 6T2QzWzsAYhIg8dJZWu10+V2HzxdgJYvW5i2FWsDpLtmfcz7lmSGl5RFN+qRiQUp5udPOa3mOL/ bNIsIpStmB3vUpA+62d+uJXO98N8MOI= X-Authority-Analysis: v=2.4 cv=K8cS2SWI c=1 sm=1 tr=0 ts=6a731b88 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=otpBJI0RWbrHn9utmiEA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA1MDA4NiBTYWx0ZWRfX4AVddGyKWssC mE+pNFiXREaLUboEkrOzqcGn9RSnWPoC74huP58Aa3WX0hYOGyMKB0/vWUM7/i98o2BPywUAnbC OEyBxrouAyf+KJFnRaRnzhyH4ZBcfjO4mKbe8f9b9FcdgiW8tE5UJESEPRDNQsCOv/v0qLwAnQq XcQPxyQYisaA5/h2lwtwA/IfeNvQDfwX64EHSXT0q+gxcgERKmLYRbJmOHRDKA3+6CNS/qXAaUr mnmUJipcFlKKgmCxNpso3nnXX22Y9a4wO8h3pmt0H37VIrbUe+xbrYeSJI7JI9iVT37qdpclA9X lqWrcMToS/bi8Tt26epdNlaEFB3GgaKMBLxobHSnm5TiPpwekBlhAdyB5cpDlyxnEtJdVGDEzYY L2DiaBR/cR+qdtvEG6hcY5diwTAeVZIRD6MQKZhkt3SNPX081klw97sqN8+aeFb8T5bbksIxlRV VGa7GlS7w2ArXoy2kSA== 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=2026-08-05_03,2026-08-04_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 spamscore=0 impostorscore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 malwarescore=0 phishscore=0 suspectscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608050086 Several sysfs show/store handlers call a discipline callback that dereferences device->private, either directly or through the DASD_DEFINE_ATTR() macro. During dasd_generic_set_online() the discipline is assigned before check_device() allocates device->private, so an unprivileged read of one of these world-readable attributes in that window dereferences a NULL pointer and panics. Guard the dereference inside each callback that actually touches device->private. Fixes: c729696bcf8b ("s390/dasd: Recognise data for ESE volumes") Cc: stable@vger.kernel.org Reviewed-by: Jan Höppner Signed-off-by: Stefan Haberland --- drivers/s390/block/dasd_eckd.c | 40 ++++++++++++++++++++++++++++++++-- 1 file changed, 38 insertions(+), 2 deletions(-) diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c index d356a9f8f016..b64ca714b53e 100644 --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -1492,6 +1492,8 @@ static void dasd_eckd_reset_path(struct dasd_device *device, __u8 pm) struct dasd_eckd_private *private = device->private; unsigned long flags; + if (!private) + return; if (!private->fcx_max_data) private->fcx_max_data = get_fcx_max_data(device); spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); @@ -1647,6 +1649,9 @@ static int dasd_eckd_is_ese(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->vsq.vol_info.ese; } @@ -1654,6 +1659,9 @@ static int dasd_eckd_ext_pool_id(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->vsq.extent_pool_id; } @@ -1667,6 +1675,9 @@ static int dasd_eckd_space_configured(struct dasd_device *device) struct dasd_eckd_private *private = device->private; int rc; + if (!private) + return 0; + rc = dasd_eckd_read_vol_info(device); return rc ? : private->vsq.space_configured; @@ -1681,6 +1692,9 @@ static int dasd_eckd_space_allocated(struct dasd_device *device) struct dasd_eckd_private *private = device->private; int rc; + if (!private) + return 0; + rc = dasd_eckd_read_vol_info(device); return rc ? : private->vsq.space_allocated; @@ -1690,6 +1704,9 @@ static int dasd_eckd_logical_capacity(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->vsq.logical_capacity; } @@ -1832,7 +1849,11 @@ static int dasd_eckd_read_ext_pool_info(struct dasd_device *device) static int dasd_eckd_ext_size(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; - struct dasd_ext_pool_sum eps = private->eps; + struct dasd_ext_pool_sum eps; + + if (!private) + return 0; + eps = private->eps; if (!eps.flags.extent_size_valid) return 0; @@ -1848,6 +1869,9 @@ static int dasd_eckd_ext_pool_warn_thrshld(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->eps.warn_thrshld; } @@ -1855,6 +1879,9 @@ static int dasd_eckd_ext_pool_cap_at_warnlevel(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->eps.flags.capacity_at_warnlevel; } @@ -1865,6 +1892,9 @@ static int dasd_eckd_ext_pool_oos(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->eps.flags.pool_oos; } @@ -5938,8 +5968,11 @@ static int dasd_eckd_query_host_access(struct dasd_device *device, struct ccw1 *ccw; int rc; + if (!private) + return -ENODEV; + /* not available for HYPER PAV alias devices */ - if (!device->block && private->lcu->pav == HYPER_PAV) + if (!device->block && private->lcu && private->lcu->pav == HYPER_PAV) return -EOPNOTSUPP; /* may not be supported by the storage server */ @@ -6804,6 +6837,9 @@ static int dasd_eckd_hpf_enabled(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->fcx_max_data ? 1 : 0; } -- 2.53.0