---
id: CVE-2026-98286
title: >-
  In the Linux kernel, the following vulnerability has been resolved:


  drop_monitor: use timer_shutdown_sync() to prevent timer rearming during
  teardown


  In drop_monitor teardown paths (net_dm_trace_off_set(),

  net_dm_hw_monitor_stop(), and…
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  drop_monitor: use timer_shutdown_sync() to prevent timer rearming during
  teardown


  In drop_monitor teardown paths (net_dm_trace_off_set(),

  net_dm_hw_monitor_stop(), and…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 9398e9c0b1d44eeb700e9e766c02bcc765c82570 <
    9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e
  - >-
    Linux >= 9398e9c0b1d44eeb700e9e766c02bcc765c82570 <
    bda4d9525fb91a2388ee09669421b8d505290864
  - >-
    Linux >= 9398e9c0b1d44eeb700e9e766c02bcc765c82570 <
    c391a40f71886b28c082b47270f0e856fa3e1150
  - Linux 2514c7ad115e762562c7bdd58bb1ab3425a98245
  - Linux 439b1164da3612ec7e186e1dc314471e7190bfc7
  - Linux >= 5.10.27 < 5.11
  - Linux >= 5.11.11 < 5.12
  - Linux 5.12
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T09:18:18.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98286'
references:
  - url: 'https://git.kernel.org/stable/c/9616b0c67fbd8cc0b49de7b26cdf2ab33747c80e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bda4d9525fb91a2388ee09669421b8d505290864'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c391a40f71886b28c082b47270f0e856fa3e1150'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-06T08:50:17.419Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown

In drop_monitor teardown paths (net_dm_trace_off_set(),
net_dm_hw_monitor_stop(), and error unwind paths in net_dm_trace_on_set()
and net_dm_hw_monitor_start()), per-CPU timers are stopped using
timer_delete_sync() followed by cancel_work_sync().

However, there is a circular dependency between send_timer and
dm_alert_work:
1) sched_send_work() (timer callback) schedules dm_alert_work.
2) send_dm_alert() / net_dm_hw_summary_work() calls reset_per_cpu_data()
   or net_dm_hw_reset_per_cpu_data().
3) If memory allocation fails under memory pressure in the reset
   function, it re-arms the timer via mod_timer(&data->send_timer, ...).

If dm_alert_work is running concurrently while timer_delete_sync()
executes on another CPU, an allocation failure in the worker will
re-arm the timer after timer_delete_sync() has already returned.
Once cancel_work_sync() completes and module_put() is called, the timer
remains active in the timer wheel. If the module is then unloaded, the
timer will fire and execute sched_send_work() in freed memory,
triggering a kernel panic / use-after-free.

Switch from timer_delete_sync() to timer_shutdown_sync(). This guarantees
that any in-flight timer handler has finished and prevents subsequent
re-arming attempts from running workers from succeeding. When monitoring
is restarted later, timer_setup() is invoked, which cleanly
re-initializes the timer.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.