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CVE-2025-39721

Description

In the Linux kernel, the following vulnerability has been resolved:crypto: qat - flush misc workqueue during device shutdownRepeated loading and unloading of a device specific QAT driver, forexample qat_4xxx, in a tight loop can lead to a crash due to ause-after-free scenario. This occurs when a power management (PM)interrupt triggers just before the device-specific driver (e.g.,qat_4xxx.ko) is unloaded, while the core driver (intel_qat.ko) remainsloaded.Since the driver uses a shared workqueue (`qat_misc_wq`) across alldevices and owned by intel_qat.ko, a deferred routine from thedevice-specific driver may still be pending in the queue. If thisroutine executes after the driver is unloaded, it can dereference freedmemory, resulting in a page fault and kernel crash like the following: BUG: unable to handle page fault for address: ffa000002e50a01c #PF: supervisor read access in kernel mode RIP: 0010:pm_bh_handler+0x1d2/0x250 [intel_qat] Call Trace: pm_bh_handler+0x1d2/0x250 [intel_qat] process_one_work+0x171/0x340 worker_thread+0x277/0x3a0 kthread+0xf0/0x120 ret_from_fork+0x2d/0x50To prevent this, flush the misc workqueue during device shutdown toensure that all pending work items are completed before the driver isunloaded.Note: This approach may slightly increase shutdown latency if theworkqueue contains jobs from other devices, but it ensures correctnessand stability.

POC

Reference

No PoCs from references.

Github

- https://github.com/fkie-cad/nvd-json-data-feeds

- https://github.com/w4zu/Debian_security