CVE-2023-54227
Memory Leak in Linux Kernel blk-mq Due to Improper Tag Freeing
Publication date: 2025-12-30
Last updated on: 2025-12-30
Assigner: kernel.org
Description
Description
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a memory leak in the Linux kernel's blk-mq subsystem related to tag management when shrinking the number of hardware queues (nr_hw_queues). Specifically, when the number of hardware queues is reduced, some allocated tags are not properly freed, causing a leak of these tags in memory.
How can this vulnerability impact me? :
The impact of this vulnerability is a memory leak in the kernel, which can lead to increased memory usage over time. This could degrade system performance or stability, especially on systems that frequently change the number of hardware queues, potentially leading to resource exhaustion.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by reproducing the conditions that cause the tags leak in the Linux kernel blk-mq subsystem. The provided steps to reproduce are: 1. mount -t configfs configfs /mnt 2. modprobe null_blk nr_devices=0 submit_queues=8 3. mkdir /mnt/nullb/nullb0 4. echo 1 > /mnt/nullb/nullb0/power 5. echo 4 > /mnt/nullb/nullb0/submit_queues 6. rmdir /mnt/nullb/nullb0 These commands simulate the allocation and shrinking of hardware queues that lead to the tags leak. Monitoring kernel memory usage or debugging kernel memory leaks during these steps can help detect the vulnerability.
What immediate steps should I take to mitigate this vulnerability?
The immediate step to mitigate this vulnerability is to apply the patch or update the Linux kernel to a version where the blk-mq tags leak issue when shrinking nr_hw_queues has been fixed. Since the vulnerability is due to tags not being freed properly, ensuring the kernel includes the fix that frees these tags will prevent the leak.