Linux Kernel IRQ Mapping Flaw in mlx5 Drivers

CVE-2025-40250

What is CVE-2025-40250?

A flaw in the Linux kernel's mlx5 IRQ allocation can lead to crashes due to improper cleanup during IRQ mapping failures. Specifically, when 'request_irq()' encounters exhausted IRQ vectors, the mlx5_irq_alloc() function erroneously frees the entire resource mapping instead of only the newly added one. This mismanagement risks invalidating other existing IRQ mappings, potentially causing system instability when subsequent access attempts are made by different threads. This vulnerability is triggered under specific configurations, highlighting the importance of precise cleanup processes in driver development. Effective remediation may involve updates to the IRQ allocation logic to ensure only the erroneous mappings are affected.

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