# CVE-2023-52668: btrfs: zoned: fix lock ordering in btrfs\_zone\_activate()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-17 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.6

## Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: fix lock ordering in btrfs_zone_activate() The btrfs CI reported a lockdep warning as follows by running generic generic/129. WARNING: possible circular locking dependency detected 6.7.0-rc5+ #1 Not tainted ------------------------------------------------------ kworker/u5:5/793427 is trying to acquire lock: ffff88813256d028 (&cache->lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x5e/0x130 but task is already holding lock: ffff88810a23a318 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x34/0x130 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}: ... -> #0 (&cache->lock){+.+.}-{2:2}: ... This is because we take fs_info->zone_active_bgs_lock after a block_group's lock in btrfs_zone_activate() while doing the opposite in other places. Fix the issue by expanding the fs_info->zone_active_bgs_lock's critical section and taking it before a block_group's lock.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6f74989f5909cdec9b1274641f0fa306b15bb476
- https://git.kernel.org/stable/c/1908e9d01e5395adff68d9d308a0fb15337e6272
- https://git.kernel.org/stable/c/b18f3b60b35a8c01c9a2a0f0d6424c6d73971dc3

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