# CVE-2024-56677: powerpc/fadump: Move fadump_cma_init to setup_arch() after initmem_init()

> A kernel bug in PowerPC fadump initialization causes a system crash during boot if CMA alignment checks are bypassed, requiring a patch.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Dec 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-56677, DEBIAN-CVE-2024-56677, GHSA-gwjv-8q72-w8xf, ROOT-OS-UBUNTU-2204-CVE-2024-56677, UBUNTU-CVE-2024-56677

## What is CVE-2024-56677?

CVE-2024-56677 is a high-severity denial of service vulnerability in Linux kernel, published on 28 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

powerpc/fadump: Move fadump_cma_init to setup_arch() after initmem_init()

During early init CMA_MIN_ALIGNMENT_BYTES can be PAGE_SIZE,
since pageblock_order is still zero and it gets initialized
later during initmem_init() e.g.
setup_arch() -> initmem_init() -> sparse_init() -> set_pageblock_order()

One such use case where this causes issue is -
early_setup() -> early_init_devtree() -> fadump_reserve_mem() -> fadump_cma_init()

This causes CMA memory alignment check to be bypassed in
cma_init_reserved_mem(). Then later cma_activate_area() can hit
a VM_BUG_ON_PAGE(pfn & ((1 << order) - 1)) if the reserved memory
area was not pageblock_order aligned.

Fix it by moving the fadump_cma_init() after initmem_init(),
where other such cma reservations also gets called.

<stack trace>
==============
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10010
flags: 0x13ffff800000000(node=1|zone=0|lastcpupid=0x7ffff) CMA
raw: 013ffff800000000 5deadbeef0000100 5deadbeef0000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: VM_BUG_ON_PAGE(pfn & ((1 << order) - 1))
------------[ cut here ]------------
kernel BUG at mm/page_alloc.c:778!

Call Trace:
__free_one_page+0x57c/0x7b0 (unreliable)
free_pcppages_bulk+0x1a8/0x2c8
free_unref_page_commit+0x3d4/0x4e4
free_unref_page+0x458/0x6d0
init_cma_reserved_pageblock+0x114/0x198
cma_init_reserved_areas+0x270/0x3e0
do_one_initcall+0x80/0x2f8
kernel_init_freeable+0x33c/0x530
kernel_init+0x34/0x26c
ret_from_kernel_user_thread+0x14/0x1c

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2024-56677?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-56677?

Apply the vendor's patch.

## Is CVE-2024-56677 being exploited?

There is no known exploitation of CVE-2024-56677 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-56677 and fix it if it is affected.

What it is: CVE-2024-56677 is a high-severity denial of service vulnerability in Linux kernel, published on 28 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-56677 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-56677/ (Markdown: https://insights.sbomify.com/CVE-2024-56677/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-56677
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-56677
- OSV: https://osv.dev/vulnerability/CVE-2024-56677

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-56677/
Summaries are generated and may contain mistakes; the official description above is the record.