Cloudanix VulnDB

CVE-2024-53176

None

CVSS

—

EPSS

0.6%

Published

Dec 27, 2024

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in safely closing network file shares can cause computers to crash during routine disconnection under certain timing conditions.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Denial Of Service
Component
OS kernel
Class
Race Condition
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Race condition in CIFS unmount (cifs_kill_sb) with cached directory operations prevents dentries from being dropped, resulting in kernel BUG at fs/super.c and VFS busy inode warnings.

Why it matters to the business

Unmounting network file shares can trigger unexpected system crashes or instability, disrupting operations especially in environments with frequent CIFS usage or server reconnections.

How an attack unfolds

Local processes or concurrent lease breaks, server reconnections, or laundromat thread activity race with unmount cleanup of cfids, leaving dentries referenced and causing the kernel to panic on unmount.

How to fix it

Update to a kernel containing the fix that moves dentry drop to cfid_put_wq workqueue, flushes it in close_all_cached_dirs, adds locking, and separates serverclose_wq work. Reboot after kernel upgrade.

How to confirm the fix worked

Confirm kernel version includes the dentry drop fix; reproduce unmount under load with concurrent cached dir operations and verify absence of BUG at fs/super.c:661.

Typical attack path

  1. Mount CIFS share and populate cached directories
  2. Trigger concurrent operations such as lease breaks or invalidation
  3. Initiate unmount while cfid cleanup is in progress
  4. Observe dentry reference leak leading to BUG

How to detect it

Review kernel logs for BUG messages referencing dentries still in use during cifs unmount or VFS busy inodes after cifs unmount; inspect for cfid cleanup races via dmesg or journalctl.

What your security team should do

  • Prioritize kernel updates for systems using CIFS mounts
  • Test unmount behavior under concurrent directory caching scenarios
  • Monitor for kernel BUG reports involving cifs and dentries

The record

In the Linux kernel, the following vulnerability has been resolved: smb: During unmount, ensure all cached dir instances drop their dentry The unmount process (cifs_kill_sb() calling close_all_cached_dirs()) can race with various cached directory operations, which ultimately results in dentries not being dropped and these kernel BUGs: BUG: Dentry ffff88814f37e358{i=1000000000080,n=/} still in use (2) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) ------------[ cut here ]------------ kernel BUG at fs/super.c:661! This happens when a cfid is in the process of being cleaned up when, and has been removed from the cfids->entries list, including: - Receiving a lease break from the server - Server reconnection triggers invalidate_all_cached_dirs(), which removes all the cfids from the list - The laundromat thread decides to expire an old cfid. To solve these problems, dropping the dentry is done in queued work done in a newly-added cfid_put_wq workqueue, and close_all_cached_dirs() flushes that workqueue after it drops all the dentries of which it's aware. This is a global workqueue (rather than scoped to a mount), but the queued work is minimal. The final cleanup work for cleaning up a cfid is performed via work queued in the serverclose_wq workqueue; this is done separate from dropping the dentries so that close_all_cached_dirs() doesn't block on any server operations. Both of these queued works expect to invoked with a cfid reference and a tcon reference to avoid those objects from being freed while the work is ongoing. While we're here, add proper locking to close_all_cached_dirs(), and locking around the freeing of cfid->dentry.

Affected packages

Ecosystem Package Introduced Fixed
Debian:12 linux 0 No fix
Debian:13 linux 0 6.12.3-1
Linux Kernel 6.1.0 6.6.64
SUSE:Linux Enterprise High Availability Extension 15 SP6 kernel-default 0 6.4.0-150600.23.42.2
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-64kb 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-default 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-default-base 0 5.14.21-150500.55.100.1.150500.6.47.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-docs 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-obs-build 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-source 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-syms 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-64kb 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-default 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-default-base 0 5.14.21-150500.55.100.1.150500.6.47.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-docs 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-obs-build 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-source 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-syms 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Live Patching 15 SP5 kernel-default 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_25 0 1-150500.11.3.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-default 0 6.4.0-150600.23.42.2
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_9 0 1-150600.1.3.2
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_9 0 1-150600.13.3.4
SUSE:Linux Enterprise Micro 5.5 kernel-default 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Micro 5.5 kernel-default-base 0 5.14.21-150500.55.100.1.150500.6.47.1
SUSE:Linux Enterprise Micro 5.5 kernel-rt 0 5.14.21-150500.13.91.1
SUSE:Linux Enterprise Micro 5.5 kernel-source 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Micro 5.5 kernel-source-rt 0 5.14.21-150500.13.91.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-64kb 0 6.4.0-150600.23.42.2
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default 0 6.4.0-150600.23.42.2
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default-base 0 6.4.0-150600.23.42.2.150600.12.18.4
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-source 0 6.4.0-150600.23.42.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-zfcpdump 0 6.4.0-150600.23.42.2
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-coco 0 6.4.0-15061.21.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-coco_debug 0 6.4.0-15061.21.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-source-coco 0 6.4.0-15061.21.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-syms-coco 0 6.4.0-15061.21.coco15sp6.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-docs 0 6.4.0-150600.23.42.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-obs-build 0 6.4.0-150600.23.42.2
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-source 0 6.4.0-150600.23.42.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-syms 0 6.4.0-150600.23.42.1
SUSE:Linux Enterprise Module for Legacy 15 SP6 kernel-default 0 6.4.0-150600.23.42.2
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-azure 0 6.4.0-150600.8.31.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-source-azure 0 6.4.0-150600.8.31.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-syms-azure 0 6.4.0-150600.8.31.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-64kb 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-default 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-default-base 0 5.14.21-150500.55.100.1.150500.6.47.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-docs 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-obs-build 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-source 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-syms 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-zfcpdump 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-default 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-default-base 0 5.14.21-150500.55.100.1.150500.6.47.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-docs 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-obs-build 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-source 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-syms 0 5.14.21-150500.55.100.1
SUSE:Linux Enterprise Workstation Extension 15 SP6 kernel-default 0 6.4.0-150600.23.42.2
SUSE:Real Time Module 15 SP6 kernel-rt 0 6.4.0-150600.10.29.1
SUSE:Real Time Module 15 SP6 kernel-rt_debug 0 6.4.0-150600.10.29.1
SUSE:Real Time Module 15 SP6 kernel-source-rt 0 6.4.0-150600.10.29.1
SUSE:Real Time Module 15 SP6 kernel-syms-rt 0 6.4.0-150600.10.29.1
Ubuntu:16.04:LTS linux-hwe-edge 0 No fix
Ubuntu:18.04:LTS linux-aws-5.0 0 No fix
Ubuntu:18.04:LTS linux-aws-5.3 0 No fix
Ubuntu:18.04:LTS linux-azure 0 No fix
Ubuntu:18.04:LTS linux-azure-5.3 0 No fix
Ubuntu:18.04:LTS linux-azure-edge 0 No fix
Ubuntu:18.04:LTS linux-gcp 0 No fix
Ubuntu:18.04:LTS linux-gcp-5.3 0 No fix
Ubuntu:18.04:LTS linux-gke-4.15 0 No fix
Ubuntu:18.04:LTS linux-gke-5.4 0 No fix
Ubuntu:18.04:LTS linux-gkeop-5.4 0 No fix
Ubuntu:18.04:LTS linux-hwe 0 No fix
Ubuntu:18.04:LTS linux-hwe-edge 0 No fix
Ubuntu:18.04:LTS linux-oem 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.0 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.3 0 No fix
Ubuntu:20.04:LTS linux 0 No fix
Ubuntu:20.04:LTS linux-aws 0 No fix
Ubuntu:20.04:LTS linux-aws-5.11 0 No fix
Ubuntu:20.04:LTS linux-aws-5.13 0 No fix
Ubuntu:20.04:LTS linux-aws-5.15 0 No fix
Ubuntu:20.04:LTS linux-aws-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure 0 No fix
Ubuntu:20.04:LTS linux-azure-5.11 0 No fix
Ubuntu:20.04:LTS linux-azure-5.13 0 No fix
Ubuntu:20.04:LTS linux-azure-5.15 0 No fix
Ubuntu:20.04:LTS linux-azure-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure-fde 0 No fix
Ubuntu:20.04:LTS linux-azure-fde-5.15 0 No fix
Ubuntu:20.04:LTS linux-bluefield 0 No fix
Ubuntu:20.04:LTS linux-gcp 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.11 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.13 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.15 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.8 0 No fix
Ubuntu:20.04:LTS linux-gke 0 No fix
Ubuntu:20.04:LTS linux-gke-5.15 0 No fix
Ubuntu:20.04:LTS linux-gkeop 0 No fix
Ubuntu:20.04:LTS linux-gkeop-5.15 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.11 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.13 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.15 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.8 0 No fix
Ubuntu:20.04:LTS linux-ibm 0 No fix
Ubuntu:20.04:LTS linux-ibm-5.15 0 No fix
Ubuntu:20.04:LTS linux-intel-5.13 0 No fix
Ubuntu:20.04:LTS linux-intel-iotg-5.15 0 No fix
Ubuntu:20.04:LTS linux-iot 0 No fix
Ubuntu:20.04:LTS linux-kvm 0 No fix
Ubuntu:20.04:LTS linux-lowlatency-hwe-5.15 0 No fix
Ubuntu:20.04:LTS linux-oem-5.10 0 No fix
Ubuntu:20.04:LTS linux-oem-5.13 0 No fix
Ubuntu:20.04:LTS linux-oem-5.14 0 No fix
Ubuntu:20.04:LTS linux-oem-5.6 0 No fix
Ubuntu:20.04:LTS linux-oracle 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.11 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.13 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.15 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.8 0 No fix
Ubuntu:20.04:LTS linux-raspi 0 No fix
Ubuntu:20.04:LTS linux-raspi2 0 No fix
Ubuntu:20.04:LTS linux-riscv 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.11 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.15 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.8 0 No fix
Ubuntu:20.04:LTS linux-xilinx-zynqmp 0 No fix
Ubuntu:22.04:LTS linux 0 No fix
Ubuntu:22.04:LTS linux-allwinner-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws 0 No fix
Ubuntu:22.04:LTS linux-aws-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws-6.2 0 No fix
Ubuntu:22.04:LTS linux-aws-6.5 0 No fix
Ubuntu:22.04:LTS linux-aws-6.8 0 No fix
Ubuntu:22.04:LTS linux-aws-6.8 0 6.8.0-1027.29~22.04.1
Ubuntu:22.04:LTS linux-azure 0 No fix
Ubuntu:22.04:LTS linux-azure-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-6.2 0 No fix
Ubuntu:22.04:LTS linux-azure-6.5 0 No fix
Ubuntu:22.04:LTS linux-azure-6.8 0 No fix
Ubuntu:22.04:LTS linux-azure-6.8 0 6.8.0-1027.32~22.04.1
Ubuntu:22.04:LTS linux-azure-fde 0 No fix
Ubuntu:22.04:LTS linux-azure-fde-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-fde-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp 0 No fix
Ubuntu:22.04:LTS linux-gcp-5.19 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.5 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.8 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.8 0 6.8.0-1028.30~22.04.1
Ubuntu:22.04:LTS linux-gke 0 No fix
Ubuntu:22.04:LTS linux-gkeop 0 No fix
Ubuntu:22.04:LTS linux-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.5 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.8 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.8 0 6.8.0-58.60~22.04.1
Ubuntu:22.04:LTS linux-ibm 0 No fix
Ubuntu:22.04:LTS linux-ibm-6.8 0 6.8.0-1024.24~22.04.1
Ubuntu:22.04:LTS linux-intel-iot-realtime 0 No fix
Ubuntu:22.04:LTS linux-intel-iotg 0 No fix
Ubuntu:22.04:LTS linux-kvm 0 No fix
Ubuntu:22.04:LTS linux-lowlatency 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.5 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.8 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.8 0 6.8.0-58.60.1~22.04.1
Ubuntu:22.04:LTS linux-nvidia 0 No fix
Ubuntu:22.04:LTS linux-nvidia-6.2 0 No fix
Ubuntu:22.04:LTS linux-nvidia-6.5 0 No fix
Ubuntu:22.04:LTS linux-nvidia-6.8 0 No fix
Ubuntu:22.04:LTS linux-nvidia-6.8 0 6.8.0-1026.29~22.04.1
Ubuntu:22.04:LTS linux-nvidia-tegra 0 No fix
Ubuntu:22.04:LTS linux-nvidia-tegra-igx 0 No fix
Ubuntu:22.04:LTS linux-oem-5.17 0 No fix
Ubuntu:22.04:LTS linux-oem-6.0 0 No fix
Ubuntu:22.04:LTS linux-oem-6.1 0 No fix
Ubuntu:22.04:LTS linux-oem-6.5 0 No fix
Ubuntu:22.04:LTS linux-oracle 0 No fix
Ubuntu:22.04:LTS linux-oracle-6.5 0 No fix
Ubuntu:22.04:LTS linux-oracle-6.8 0 No fix
Ubuntu:22.04:LTS linux-oracle-6.8 0 6.8.0-1024.25~22.04.1
Ubuntu:22.04:LTS linux-raspi 0 No fix
Ubuntu:22.04:LTS linux-realtime 0 No fix
Ubuntu:22.04:LTS linux-riscv 0 No fix
Ubuntu:22.04:LTS linux-riscv-5.19 0 No fix
Ubuntu:22.04:LTS linux-riscv-6.5 0 No fix
Ubuntu:22.04:LTS linux-riscv-6.8 0 No fix
Ubuntu:22.04:LTS linux-riscv-6.8 0 6.8.0-58.60.1~22.04.1
Ubuntu:22.04:LTS linux-starfive-5.19 0 No fix
Ubuntu:22.04:LTS linux-starfive-6.2 0 No fix
Ubuntu:22.04:LTS linux-starfive-6.5 0 No fix
Ubuntu:22.04:LTS linux-xilinx-zynqmp 0 No fix
Ubuntu:22.04:LTS:for:NVIDIA:BlueField linux-bluefield 0 No fix
Ubuntu:24.04:LTS linux 0 No fix
Ubuntu:24.04:LTS linux 0 6.8.0-58.60

Related vulnerabilities