In the Linux kernel, the following vulnerability has been resolved:
s390/mm: Add NULL pointer check to crsttablefree() basecrstfree()
crsttablefree() used to work with NULL pointers before the conversion to ptdescs. Since crsttablefree() can be called with a NULL pointer (error handling in crsttableupgrade() add an explicit check.
Also add the same check to basecrstfree() for consistency reasons.
In real life this should not happen, since order two GFPKERNEL allocations will not fail, unless FAILPAGE_ALLOC is enabled and used.