CVE-2024-57884: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-57884 is a vulnerability in the Linux kernel discovered in January 2025 that causes the kernel to hang due to a task becoming stuck in throttledirectreclaim(). This occurs when a node is incorrectly deemed balanced despite pressure in certain memory zones (NVD).

The vulnerability arises when zonereclaimablepages() returns 0 for zones without reclaimable file-backed or anonymous pages, causing zones like ZONEDMA32 with sufficient free pages to be skipped during memory reclaim. The issue manifests when a system lacks swap space or reclaimable pages, resulting in ZONEDMA32 being ignored during reclaim and masking pressure in other zones. This leads to pgdat->kswapdfailures remaining at 0 in balancepgdat(), which prevents fallback mechanisms in allowdirectreclaim() from triggering, ultimately causing an infinite loop in throttledirectreclaim() (Kernel Patch).

The vulnerability results in a kernel hang condition where tasks become stuck in throttledirectreclaim(), potentially affecting system stability and performance. This occurs particularly in systems with specific memory zone configurations where some zones have sufficient free pages while others are under pressure (Kernel Patch).

A patch has been developed that modifies zonereclaimablepages() to account for free pages (NRFREEPAGES) when no other reclaimable pages exist. This ensures zones with sufficient free pages are not skipped, enabling proper balancing and reclaim behavior. The fix has been incorporated into various Linux kernel versions through stable updates (Debian LTS).