CVE-2022-50546

An uninitialized variable flaw was found in the Linux kernel's ext4 filesystem in the inode eviction path. A local user can trigger this issue by creating filesystem operations that cause inode allocation to fail before the i_flags field is initialized, followed by inode cleanup that attempts to read the uninitialized field. This causes the kernel to access uninitialized memory, resulting in unpredictable behavior and denial of service through a kernel crash.

The ext4_alloc_inode function allocates memory for new inodes but fails to initialize the ei->i_flags field. When __ext4_new_inode encounters an error before setting i_flags and calls iput to clean up, the subsequent ext4_evict_inode function attempts to read the uninitialized i_flags value. This accesses undefined memory contents, triggering KMSAN (Kernel Memory Sanitizer) warnings and potentially causing kernel crashes or unpredictable behavior. The issue occurs during normal filesystem operations like mkdir or mknod when inode allocation fails partway through, which can happen under memory pressure or filesystem corruption. Any local user performing filesystem operations on ext4 volumes can potentially trigger this condition.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.