CVE-2026-80679: s390/dasd: Fix potential NULL pointer dereference

CVE-2026-80679: s390/dasd: Fix potential NULL pointer dereference

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

s390/dasd: Fix potential NULL pointer dereference

dasd_release_space() checks the implementation of the is_ese()
discipline function before calling it to determine if a given device is
an ESE DASD.

The current usage of the logical AND operator will lead to a NULL
pointer dereference as the function is called even if the function
pointer is NULL.

Fix this by using the logical OR operator.

The Linux kernel CVE team has assigned CVE-2026-80679 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 5.10.265 with commit dbf2ae34d2f1390a9fc1abf3dce7f809e022caae
	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 5.15.216 with commit 3000367a512b1283ca52230bf21f8c91dfbec45b
	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 6.1.183 with commit cdc7b73d0c5a9cd6360b4f8c36eae23b02097e4c
	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 6.6.151 with commit e156c70c505c6c9adce3b7be5a82025f00544709
	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 6.12.103 with commit 3453a993a3f14c1684560ecf26585046976f6ac6
	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 6.18.44 with commit 86cdfd061509bcde84f3145f7221ba64e3e53b1f
	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 7.1.8 with commit 96b8e09b09539f252a5eeea6baebd93c2e3779bd
	Issue introduced in 5.3 with commit 91dc4a197569230683ca8bad551e655a4bf14c30 and fixed in 7.2 with commit 9973026f572db6b67570cadc30942f3014e41079

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-80679
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/s390/block/dasd_ioctl.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/dbf2ae34d2f1390a9fc1abf3dce7f809e022caae
	https://git.kernel.org/stable/c/3000367a512b1283ca52230bf21f8c91dfbec45b
	https://git.kernel.org/stable/c/cdc7b73d0c5a9cd6360b4f8c36eae23b02097e4c
	https://git.kernel.org/stable/c/e156c70c505c6c9adce3b7be5a82025f00544709
	https://git.kernel.org/stable/c/3453a993a3f14c1684560ecf26585046976f6ac6
	https://git.kernel.org/stable/c/86cdfd061509bcde84f3145f7221ba64e3e53b1f
	https://git.kernel.org/stable/c/96b8e09b09539f252a5eeea6baebd93c2e3779bd
	https://git.kernel.org/stable/c/9973026f572db6b67570cadc30942f3014e41079