Concurrency Management Flaw in Linux Kernel s390/ism Driver

CVE-2025-39726

What is CVE-2025-39726?

The Linux kernel's s390/ism driver fails to enforce the requirement of processing only one request-response sequence at a time per ISM function. This oversight can lead to multiple commands being issued simultaneously, risking data corruption and erroneous execution. Specific workloads may trigger the ISM functions to enter an error state, indicated by logging errors such as PEC 2, which can disable recovery mechanisms. The absence of synchronization means that commands could overlap, causing invalid data usage, command loss, or execution of incorrect commands altogether, thus jeopardizing system reliability and functionality.

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