CVE-2025-39939

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

iommu/s390: Fix memory corruption when using identity domain

zpcigetiommuctrs() returns counter information to be reported as part of device statistics; these counters are stored as part of the s390domain. The problem, however, is that the identity domain is not backed by an s390domain and so the conversion via tos390_domain() yields a bad address that is zero'd initially and read on-demand later via a sysfs read. These counters aren't necessary for the identity domain; just return NULL in this case.

This issue was discovered via KASAN with reports that look like: BUG: KASAN: global-out-of-bounds in zpcifmbenable_device when using the identity domain for a device on s390.