Linux Kernel Softlockup in kdump Memory Processing

CVE-2025-21694

Summary

In the Linux kernel, an issue was identified concerning softlockups during kdump memory processing. While improvements were made to reduce softlockups with a recent commit, occurrences still arise, particularly in memory-constrained environments where kdump operates. These softlockups can disrupt critical functions such as RCU memory freeing, effectively hindering the dump process. To mitigate this, a new condition for rescheduling was introduced in the second loop of the __read_vmcore function, aiming to enhance responsiveness during data write operations.

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