---
id: CVE-2022-49802
title: 'ftrace: Fix null pointer dereference in ftrace_add_mod()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ftrace: Fix null pointer dereference in ftrace_add_mod()

  The @ftrace_mod is allocated by kzalloc(), so both the members {prev,next}
  of @ftrace_mode->list are NULL, it'…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 <
    665b4c6648bf2b91f69b33817f4321cf4c3cafe9
  - >-
    Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 <
    b5bfc61f541d3f092b13dedcfe000d86eb8e133c
  - >-
    Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 <
    f715f31559b82e3f75ce047fa476de63d8107584
  - >-
    Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 <
    6a14828caddad0d989495a72af678adf60992704
  - >-
    Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 <
    1bea037a1abb23a6729bef36a2265a4565f5ea77
  - >-
    Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 <
    6e50eb4b1807017f6c2d5089064256ce2de8aef1
  - >-
    Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 <
    19ba6c8af9382c4c05dc6a0a79af3013b9a35cd0
  - Linux 4.13
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T19:48:54.647011Z'
published: '2025-05-01'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T19:49:50.009Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2022-49802'
references:
  - url: 'https://git.kernel.org/stable/c/665b4c6648bf2b91f69b33817f4321cf4c3cafe9'
  - url: 'https://git.kernel.org/stable/c/b5bfc61f541d3f092b13dedcfe000d86eb8e133c'
  - url: 'https://git.kernel.org/stable/c/f715f31559b82e3f75ce047fa476de63d8107584'
  - url: 'https://git.kernel.org/stable/c/6a14828caddad0d989495a72af678adf60992704'
  - url: 'https://git.kernel.org/stable/c/1bea037a1abb23a6729bef36a2265a4565f5ea77'
  - url: 'https://git.kernel.org/stable/c/6e50eb4b1807017f6c2d5089064256ce2de8aef1'
  - url: 'https://git.kernel.org/stable/c/19ba6c8af9382c4c05dc6a0a79af3013b9a35cd0'
tags:
  - cve.org
epss: 0.00222
epssPercentile: 0.12907
ingestedAt: '2026-11-05T22:38:31.598Z'
---

## Overview

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

ftrace: Fix null pointer dereference in ftrace_add_mod()

The @ftrace_mod is allocated by kzalloc(), so both the members {prev,next}
of @ftrace_mode->list are NULL, it's not a valid state to call list_del().
If kstrdup() for @ftrace_mod->{func|module} fails, it goes to @out_free
tag and calls free_ftrace_mod() to destroy @ftrace_mod, then list_del()
will write prev->next and next->prev, where null pointer dereference
happens.

BUG: kernel NULL pointer dereference, address: 0000000000000008
Oops: 0002 [#1] PREEMPT SMP NOPTI
Call Trace:
 <TASK>
 ftrace_mod_callback+0x20d/0x220
 ? do_filp_open+0xd9/0x140
 ftrace_process_regex.isra.51+0xbf/0x130
 ftrace_regex_write.isra.52.part.53+0x6e/0x90
 vfs_write+0xee/0x3a0
 ? __audit_filter_op+0xb1/0x100
 ? auditd_test_task+0x38/0x50
 ksys_write+0xa5/0xe0
 do_syscall_64+0x3a/0x90
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
Kernel panic - not syncing: Fatal exception

So call INIT_LIST_HEAD() to initialize the list member to fix this issue.

## Affected

- `Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 < 665b4c6648bf2b91f69b33817f4321cf4c3cafe9`
- `Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 < b5bfc61f541d3f092b13dedcfe000d86eb8e133c`
- `Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 < f715f31559b82e3f75ce047fa476de63d8107584`
- `Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 < 6a14828caddad0d989495a72af678adf60992704`
- `Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 < 1bea037a1abb23a6729bef36a2265a4565f5ea77`
- `Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 < 6e50eb4b1807017f6c2d5089064256ce2de8aef1`
- `Linux >= 673feb9d76ab3eddde7acfd94b206e321cfc90b9 < 19ba6c8af9382c4c05dc6a0a79af3013b9a35cd0`
- `Linux 4.13`

## Remediation

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