CVE-2026-98930: KVM: s390: Fix IRQ injection with SIGP Stop and Store Status

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-23 · updated 2026-10-23

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Fix IRQ injection with SIGP Stop and Store Status When __inject_sigp_stop() is called for a Stop and Store Status operation, if the vCPU is running, the interrupt is marked as pending and the status is stored by the thread performing the KVM_RUN IOCTL. If the vCPU is already stopped, the status is stored immediately. Storing the status means writing into userspace, which might fault, and __inject_sigp_stop() is called from do_inject_vcpu() which in turn is always called holding a spinlock, which is obviously an issue. Fix this by returning -EWOULDBLOCK from __inject_sigp_stop(), and adding a bool flag to indicate whether a store status is needed. The callers of do_inject_vcpu() are modified to pass the pointer to the bool flag; whenever a Store Status operation is needed, the callers can now perform it outside the spinlock. Opportunistically refactor kvm_s390_set_irq_state() to use scoped_guard() and __free(). [ Added Fixes tag while picking -- Claudio ]

Affected products

Linux kernel: 4.0 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

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