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Fencer Vulns
medium 5.5

CVE-2024-56565 json

f2fs: fix to drop all discards after creating snapshot on lvm device

published 2024-12-27 22 mo ago modified 2026-10-30 9 d ago also EUVD-2024-53213

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

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

f2fs: fix to drop all discards after creating snapshot on lvm device

Piergiorgio reported a bug in bugzilla as below:

------------[ cut here ]------------ WARNING: CPU: 2 PID: 969 at fs/f2fs/segment.c:1330 RIP: 0010:__submit_discard_cmd+0x27d/0x400 [f2fs] Call Trace: __issue_discard_cmd+0x1ca/0x350 [f2fs] issue_discard_thread+0x191/0x480 [f2fs] kthread+0xcf/0x100 ret_from_fork+0x31/0x50 ret_from_fork_asm+0x1a/0x30

w/ below testcase, it can reproduce this bug quickly: - pvcreate /dev/vdb - vgcreate myvg1 /dev/vdb - lvcreate -L 1024m -n mylv1 myvg1 - mount /dev/myvg1/mylv1 /mnt/f2fs - dd if=/dev/zero of=/mnt/f2fs/file bs=1M count=20 - sync - rm /mnt/f2fs/file - sync - lvcreate -L 1024m -s -n mylv1-snapshot /dev/myvg1/mylv1 - umount /mnt/f2fs

The root cause is: it will update discard_max_bytes of mounted lvm device to zero after creating snapshot on this lvm device, then, __submit_discard_cmd() will pass parameter @nr_sects w/ zero value to __blkdev_issue_discard(), it returns a NULL bio pointer, result in panic.

This patch changes as below for fixing: 1. Let's drop all remained discards in f2fs_unfreeze() if snapshot of lvm device is created. 2. Checking discard_max_bytes before submitting discard during __submit_discard_cmd().

Patch / fix

  • Linux Linux 6.1.191, 6.6.66, 6.12.4, 6.13
  • linux Debian 14, Debian 13 6.12.5-1

debian advisories DEBIAN-CVE-2024-56565

  • linux Ubuntu 24.04 LTS 6.8.0-58.60
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1027.29
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1028.30
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1023.27
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1024.24
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1027.32
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1010.12
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1028.32

ubuntu advisories UBUNTU-CVE-2024-56565

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-56565 updated

kernel: f2fs: fix to drop all discards after creating snapshot on lvm device

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.