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Sat, 1 Aug 2026 11:10:16 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Sat, 1 Aug 2026 11:10:16 +0000 (GMT) From: Stefan Haberland To: linux-s390@vger.kernel.org Cc: Jan Hoeppner , Eduard Shishkin Subject: [PATCH v6 03/18] s390/dasd: Guard sysfs discipline callbacks against unallocated private data Date: Sat, 1 Aug 2026 13:09:53 +0200 Message-ID: <20260801111008.3391031-4-sth@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260801111008.3391031-1-sth@linux.ibm.com> References: <20260801111008.3391031-1-sth@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=E6P9Y6dl c=1 sm=1 tr=0 ts=6a6dd41e cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=otpBJI0RWbrHn9utmiEA:9 X-Proofpoint-ORIG-GUID: 70YHyGQYZql89evv3pkvjxLC6BrKvUjN X-Proofpoint-GUID: 70YHyGQYZql89evv3pkvjxLC6BrKvUjN X-Proofpoint-Spam-Info: AW1haW4tMjYwODAxMDA4MyBTYWx0ZWRfX7qbJN12cktXH 32uQvM5XgAsdDCj+JZSJvMUmH2lGSuoMnyBU+jx2VqPuxhQBegifdOjx+kVDZw/yUGWopqeqIDb KE+F0QMZLYGzPiFcNAnoIMuOvCAe6N0= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODAxMDA4MyBTYWx0ZWRfXxDXcK9Fm+fq6 yzkzUwrQ4Sjw6BlQmHJjoVWDNHGWs+g+BZAmJHiN4VUyA2rQghHd8ISzFKCKYHwS4BRmB50HJUh KK+/xZ9TAnIhAh9f9XTYdBZd9N1Zir6aZrm5+iUuDuerKzr/hhu3g0kPAwG+/JtJyqFMr38UbDX rZUJtPMRX3HdVh1bCC9HaZESrVA6op9LQzES4Jp+j923i9AmqAE7Mn2g5P2YZ7mj9zwMjtYvWVb LSxEyD4zuBDN7XpJgnqLy1XBcPePJKqyQ9eJzh4v7aPvCH+LqRZ2Au3JsyBsgedi0riOoKE7Is+ 4D0V4aKuEpQr/isrjza7NbwJ9PZ7N2GnZ+wIB2/RX7qpJuoHhzMSi70NSwBxO2apSp7w/Z8whyg b4eI/+PVwbIeUW/HNDtSve+i+ClOHX2ZPzDsiTIGVioAwhBoN5xJXCPm1ZagRUW7w/xEetr3uMh ds8r++owAHq+9IhOrrQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-31_07,2026-07-30_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 impostorscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608010083 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 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 073795ea7cd0..7ce8a82d951d 100644 --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -1491,6 +1491,8 @@ 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); @@ -1646,6 +1648,9 @@ 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; } @@ -1653,6 +1658,9 @@ 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; } @@ -1666,6 +1674,9 @@ 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; @@ -1680,6 +1691,9 @@ 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; @@ -1689,6 +1703,9 @@ 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; } @@ -1831,7 +1848,11 @@ 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; @@ -1847,6 +1868,9 @@ 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; } @@ -1854,6 +1878,9 @@ 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; } @@ -1864,6 +1891,9 @@ 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; } @@ -5935,8 +5965,11 @@ 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 */ @@ -6801,6 +6834,9 @@ 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