In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Fix potential races in dat skey functions When… (CVE-2026-98650)

This vulnerability in the Linux kernel affects the KVM s390 code handling storage key functions. Specifically, dat_cond_set_storage_key() and dat_set_storage_key() could encounter race conditions when large pages are concurrently split, causing the function large_crste_to_phys() to be called with invalid crste pointers. This could lead to kernel crashes. The functions dat_get_storage_key() and dat_reset_reference_bit() also mishandled concurrent splitting. The fix applies READ_ONCE to safely read the crste pointer and retries the operation if a race is detected, preventing crashes caused by dereferencing invalid pointers.

The vulnerability can cause kernel crashes due to race conditions when handling large page storage keys in the KVM s390 subsystem. This could affect system stability and reliability but no information about privilege escalation or code execution is provided.

A fix has been applied to the Linux kernel to address this race condition by using safer pointer access and retry logic. Users should update to the patched kernel version once available. No other mitigation steps are indicated.