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.