CVE-2025-21817
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In the Linux kernel, a vulnerability was found where a potential deadlock can occur during sysfs ->store() calls. The issue arises when store callbacks (e.g., update_nr_requests, wbt, scheduler) allocate memory with GFP_KERNEL, which may trigger direct reclaim and deadlock while the queue is frozen. The fix marks the context with GFP_NOIO around sysfs ->store().
Risk Assessment
A deadlock could cause complete system hang or block I/O operations, leading to service unavailability and potential data loss.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit addressing the issue). Monitor official security advisories from your Linux distribution for the appropriate patch.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: block: mark GFP_NOIO around sysfs ->store() sysfs ->store is called with queue freezed, meantime we have several ->store() callbacks(update_nr_requests, wbt, scheduler) to allocate memory with GFP_KERNEL which may run into direct reclaim code path, then potential deadlock can be caused. Fix the issue by marking NOIO around sysfs ->store()