CVE-2022-49220: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-49220 affects the Linux kernel's DAX (Direct Access) filesystem module. The vulnerability was discovered when a bug could be triggered by executing the command sequence 'modprobe ndpmem && modprobe -r ndpmem', which resulted in objects remaining in daxcache during _kmemcacheshutdown(). This issue was caused by daxfsexit() not properly flushing inodes before destroying the cache (NVD).

The vulnerability occurs in the Linux kernel's DAX module, specifically in the daxfsexit() function within the drivers/dax/super.c file. When unloading the ndpmem module, the system encounters a BUG condition in daxcache with objects remaining during cache shutdown. The issue manifests with a slab containing objects=9 and used=1, indicating improper cleanup of cache objects (Kernel Commit).

When triggered, the vulnerability causes a kernel bug condition that could potentially lead to system instability. The bug manifests when attempting to remove the ndpmem module, leaving residual objects in the daxcache during shutdown operations (NVD).

The issue has been fixed by adding an rcubarrier() call before destroying the cache in the daxfs_exit() function. This ensures that all inodes are properly flushed before the cache is destroyed. The fix was implemented in the Linux kernel through a patch that addresses the root cause of the issue (Kernel Commit).