CVEvulnerability
CVE-2023-53777
- Status
- Deferred
- Published
- 2025-12-09
- Last modified
- 2026-06-17
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Description
In the Linux kernel, the following vulnerability has been resolved:
erofs: kill hooked chains to avoid loops on deduplicated compressed images
After heavily stressing EROFS with several images which include a
hand-crafted image of repeated patterns for more than 46 days, I found
two chains could be linked with each other almost simultaneously and
form a loop so that the entire loop won't be submitted. As a
consequence, the corresponding file pages will remain locked forever.
It can be _only_ observed on data-deduplicated compressed images.
For example, consider two chains with five pclusters in total:
Chain 1: 2->3->4->5 -- The tail pcluster is 5;
Chain 2: 5->1->2 -- The tail pcluster is 2.
Chain 2 could link to Chain 1 with pcluster 5; and Chain 1 could link
to Chain 2 at the same time with pcluster 2.
Since hooked chains are all linked locklessly now, I have no idea how
to simply avoid the race. Instead, let's avoid hooked chains completely
until I could work out a proper way to fix this and end users finally
tell us that it's needed to add it back.
Actually, this optimization can be found with multi-threaded workloads
(especially even more often on deduplicated compressed images), yet I'm
not sure about the overall system impacts of not having this compared
with implementation complexity.
References
- https://git.kernel.org/stable/c/10c2b98a40d9044a3e97f4697ca6213bad7e19c2 git.kernel.org
- https://git.kernel.org/stable/c/967c28b23f6c89bb8eef6a046ea88afe0d7c1029 git.kernel.org
- https://git.kernel.org/stable/c/b5b0d52f00e4bacb0ebdf47cd7016b0485fffad2 git.kernel.org
- https://git.kernel.org/stable/c/d3b39ea24835ac03da1a30f93ae7c05d55a40191 git.kernel.org