From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF0D03E7631; Fri, 4 Sep 2026 05:56:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501369; cv=none; b=rmRIcQ4HtxoGiafTJLyKJEpcH/NUm916gA+UNWNiF4rcfzgxGrSN2sJ80eyH6pqQv654C0BQwsYJMxupDnz+5h3XLmXy5vVrlDekRpsxUb+CzQo0KAA5QSfrOXKHq0NoTsirH305MuRXHHxGTrvU6B7dBfNopas9kN7xo2ed+rQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501369; c=relaxed/simple; bh=fZiLEalhyoytqls5mdwKpWnhour13peTg0EigM/ciRo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=RivGH7tmD5pZ9RmL2/R/hIXRpj3q9uT+orCNP2v7l9rVmzXeJFhJ3aXjvFe+s9ilaCbH1Y5lqLpW8MYyj/ANZtquuuHJUYz0V3Oz/woEz8GLmTBZQGq+Y6tQplSxLIevqR2ZcCODq2RpOaLRcn4t9ujeTcnmxL4AJqTdXvMOMso= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uHIuyp4y; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uHIuyp4y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 248601F00A3D; Fri, 4 Sep 2026 05:56:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501367; bh=cxLHtMJOP79HxYEuFCT0ut9KzGlPesyYiRjS8E1oJnw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=uHIuyp4yQvElp3FhzG+rBey4MC7J5zumoTdKS584CSK8hQx+4pHhNIo93hM+u9HHm SUQIi4sPUdqmNJxiDtAMuTXFNGeTcSeYhJ161B4QbfOUE5JwBgGD1pLafamI8XORCf FqVTcN2NqUIKUUhRikuEXie4ywwhkZRwhh0NNlec= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Jan=20H=C3=B6ppner?= , Stefan Haberland , Jens Axboe Subject: [PATCH 6.18 384/552] s390/dasd: Guard sysfs discipline callbacks against unallocated private data Date: Fri, 4 Sep 2026 06:59:01 +0200 Message-ID: <20260904045758.917445931@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefan Haberland commit 2a1780f9fc2493bd34c418a0be6fc58943afcecf upstream. 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 Link: https://patch.msgid.link/20260805111612.1285190-4-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/s390/block/dasd_eckd.c | 40 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 38 insertions(+), 2 deletions(-) --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -1493,6 +1493,8 @@ static void dasd_eckd_reset_path(struct 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); @@ -1648,6 +1650,9 @@ static int dasd_eckd_is_ese(struct dasd_ { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->vsq.vol_info.ese; } @@ -1655,6 +1660,9 @@ static int dasd_eckd_ext_pool_id(struct { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->vsq.extent_pool_id; } @@ -1668,6 +1676,9 @@ static int dasd_eckd_space_configured(st 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; @@ -1682,6 +1693,9 @@ static int dasd_eckd_space_allocated(str 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; @@ -1691,6 +1705,9 @@ static int dasd_eckd_logical_capacity(st { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->vsq.logical_capacity; } @@ -1833,7 +1850,11 @@ static int dasd_eckd_read_ext_pool_info( 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; @@ -1849,6 +1870,9 @@ static int dasd_eckd_ext_pool_warn_thrsh { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->eps.warn_thrshld; } @@ -1856,6 +1880,9 @@ static int dasd_eckd_ext_pool_cap_at_war { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->eps.flags.capacity_at_warnlevel; } @@ -1866,6 +1893,9 @@ static int dasd_eckd_ext_pool_oos(struct { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->eps.flags.pool_oos; } @@ -5949,8 +5979,11 @@ static int dasd_eckd_query_host_access(s 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 */ @@ -6815,6 +6848,9 @@ static int dasd_eckd_hpf_enabled(struct { struct dasd_eckd_private *private = device->private; + if (!private) + return 0; + return private->fcx_max_data ? 1 : 0; }