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UBUNTU-CVE-2021-47119

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UBUNTU-CVE-2021-47119

Published: 15 Mar 2024Last Modified: 22 Oct 2026

Upstream:

Aliases:

Summary:

Details: In the Linux kernel, the following vulnerability has been resolved: ext4: fix memory leak in ext4_fill_super Buffer head references must be released before calling kill_bdev(); otherwise the buffer head (and its page referenced by b_data) will not be freed by kill_bdev, and subsequently that bh will be leaked. If blocksizes differ, sb_set_blocksize() will kill current buffers and page cache by using kill_bdev(). And then super block will be reread again but using correct blocksize this time. sb_set_blocksize() didn't fully free superblock page and buffer head, and being busy, they were not freed and instead leaked. This can easily be reproduced by calling an infinite loop of: systemctl start <ext4_on_lvm>.mount, and systemctl stop <ext4_on_lvm>.mount ... since systemd creates a cgroup for each slice which it mounts, and the bh leak get amplified by a dying memory cgroup that also never gets freed, and memory consumption is much more easily noticed.

Affected packages

Package

Name: linux

Purl: pkg:deb/ubuntu/linux?arch=source&distro=esm-infra-legacy%2Ftrusty

Affected ranges

Type: ECOSYSTEM

Events:

Introduced- 0

Fixed -3.13.0-205.256

Affected versions

3.11.0-12.19

Common Vulnerability Scoring System

Attack Vector

Network

Adjacent

Local

Physical

Privileges Required

None

Low

High

User Interaction

None

Required

Scope

Unchanged

Changed

Confidentiality

None

Low

High

Integrity

None

Low

High

Availability

None

Low

High