CVE-2022-50770 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix memory leak in ocfs2_mount_volume()
There is a memory leak reported by kmemleak:
unreferenced object 0xffff88810cc65e60 (size 32): comm "mount.ocfs2", pid 23753, jiffies 4302528942 (age 34735.105s) hex dump (first 32 bytes): 10 00 00 00 00 00 00 00 00 01 01 01 01 01 01 01 ................ 01 01 01 01 01 01 01 01 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff8170f73d>] __kmalloc+0x4d/0x150
[<ffffffffa0ac3f51>] ocfs2_compute_replay_slots+0x121/0x330 [ocfs2]
[<ffffffffa0b65165>] ocfs2_check_volume+0x485/0x900 [ocfs2]
[<ffffffffa0b68129>] ocfs2_mount_volume.isra.0+0x1e9/0x650 [ocfs2]
[<ffffffffa0b7160b>] ocfs2_fill_super+0xe0b/0x1740 [ocfs2]
[<ffffffff818e1fe2>] mount_bdev+0x312/0x400
[<ffffffff819a086d>] legacy_get_tree+0xed/0x1d0
[<ffffffff818de82d>] vfs_get_tree+0x7d/0x230
[<ffffffff81957f92>] path_mount+0xd62/0x1760
[<ffffffff81958a5a>] do_mount+0xca/0xe0
[<ffffffff81958d3c>] __x64_sys_mount+0x12c/0x1a0
[<ffffffff82f26f15>] do_syscall_64+0x35/0x80
[<ffffffff8300006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
This call stack is related to two problems. Firstly, the ocfs2 super uses "replay_map" to trace online/offline slots, in order to recover offline slots during recovery and mount. But when ocfs2_truncate_log_init() returns an error in ocfs2_mount_volume(), the memory of "replay_map" will not be freed in error handling path. Secondly, the memory of "replay_map" will not be freed if d_make_root() returns an error in ocfs2_fill_super(). But the memory of "replay_map" will be freed normally when completing recovery and mount in ocfs2_complete_mount_recovery().
Fix the first problem by adding error handling path to free "replay_map" when ocfs2_truncate_log_init() fails. And fix the second problem by calling ocfs2_free_replay_slots(osb) in the error handling path "out_dismount". In addition, since ocfs2_free_replay_slots() is static, it is necessary to remove its static attribute and declare it in header file.
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Analysis
by VulDB Data Team • 04/21/2026
The vulnerability CVE-2022-50770 represents a memory leak in the Linux kernel's OCFS2 (Oracle Cluster File System 2) implementation that occurs during volume mounting operations. This issue specifically affects the ocfs2_mount_volume() function where memory allocated for replay_map structures is not properly freed in error handling paths. The memory leak is detected by the kernel's kmemleak subsystem which identifies an unreferenced object of 32 bytes that remains allocated for over 34,000 seconds, indicating a persistent memory resource consumption problem. The vulnerability manifests when the kernel attempts to mount OCFS2 volumes and encounters errors during the initialization process, particularly when ocfs2_truncate_log_init() fails or when d_make_root() returns an error during superblock filling operations.
The technical flaw stems from inadequate error handling within the OCFS2 mount process, specifically in the ocfs2_mount_volume() function and its associated error paths. When ocfs2_truncate_log_init() returns an error during volume mounting, the replay_map memory allocated for tracking online/offline slots is not freed, creating a memory leak that persists until the system reboots. Similarly, when d_make_root() fails during the ocfs2_fill_super() function, the replay_map memory is also not properly released. This represents a classic resource management issue where allocated kernel memory is not returned to the system when error conditions occur, violating fundamental kernel memory management principles and potentially leading to system performance degradation or resource exhaustion over time.
The operational impact of this vulnerability is significant for systems running OCFS2 filesystems, particularly in clustered environments where high availability and stable system performance are critical. The memory leak can accumulate over time, especially in systems with frequent mount operations or in environments where OCFS2 volumes are mounted and unmounted regularly. This can lead to gradual memory consumption that may eventually impact system stability, reduce available memory for other processes, and potentially cause system slowdowns or crashes. The vulnerability affects any Linux system with OCFS2 support enabled and is particularly concerning for enterprise environments where OCFS2 is used for shared storage solutions in high-availability clusters. The issue can be exploited through normal mount operations, making it a persistent threat to system resources without requiring special privileges or specific attack vectors.
The fix for this vulnerability requires comprehensive error handling modifications to ensure proper memory cleanup in all failure paths. The solution involves adding explicit error handling to free the replay_map memory when ocfs2_truncate_log_init() fails, and implementing cleanup calls to ocfs2_free_replay_slots(osb) in the error handling path labeled "out_dismount" when d_make_root() returns an error. Additionally, the fix requires modifying the function declaration to remove the static attribute from ocfs2_free_replay_slots() and make it available in the header file, ensuring proper linkage and accessibility for cleanup operations. This approach aligns with the CWE-401 principle of "Improper Release of Memory Before Removing Last Reference" and follows ATT&CK technique T1490 for "Inhibit System Recovery" by addressing resource exhaustion through proper memory management. The fix ensures that all allocated memory is properly released regardless of whether the mount operation succeeds or fails, maintaining system stability and preventing long-term memory consumption issues that could affect overall system performance and reliability.