CVE-2026-98653

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

KVM: s390: Fix gaccess shadow fault()

In some circumstances, it is possible that the page of nested guest memory that is being shadowed is not present at all in the parent guest gmap. dat entry walk() will not find any leaf entry and return with -ENOENT, which will erroneously be propagated all the way to userspace.

Fix by manually calling gmap link() on the memory of the nested guest that is being shadowed if the mapping was not already present.