CVE-2022-49666 powerpc/memhotplug: Add add_pages override for PPC

Medium 5.5 Published 26 Feb 2025 Updated 23 May 2026

A missing memory hotplug override in the Linux kernel for PowerPC causes a kernel BUG_ON crash when using DAX PFNs, leading to denial of service.

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

What is CVE-2022-49666?

CVE-2022-49666 is a medium-severity denial of service vulnerability in Linux kernel, published on 26 Feb 2025. 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/memhotplug: Add add_pages override for PPC

With commit ffa0b64e3be5 ("powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit") the kernel now validate the addr against high_memory value. This results in the below BUG_ON with dax pfns.

[ 635.798741][T26531] kernel BUG at mm/page_alloc.c:5521! 1:mon> e cpu 0x1: Vector: 700 (Program Check) at [c000000007287630] pc: c00000000055ed48: free_pages.part.0+0x48/0x110 lr: c00000000053ca70: tlb_finish_mmu+0x80/0xd0 sp: c0000000072878d0 msr: 800000000282b033 current = 0xc00000000afabe00 paca = 0xc00000037ffff300 irqmask: 0x03 irq_happened: 0x05 pid = 26531, comm = 50-landscape-sy kernel BUG at :5521! Linux version 5.19.0-rc3-14659-g4ec05be7c2e1 (kvaneesh@ltc-boston8) (gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #625 SMP Thu Jun 23 00:35:43 CDT 2022 1:mon> t [link register ] c00000000053ca70 tlb_finish_mmu+0x80/0xd0 [c0000000072878d0] c00000000053ca54 tlb_finish_mmu+0x64/0xd0 (unreliable) [c000000007287900] c000000000539424 exit_mmap+0xe4/0x2a0 [c0000000072879e0] c00000000019fc1c mmput+0xcc/0x210 [c000000007287a20] c000000000629230 begin_new_exec+0x5e0/0xf40 [c000000007287ae0] c00000000070b3cc load_elf_binary+0x3ac/0x1e00 [c000000007287c10] c000000000627af0 bprm_execve+0x3b0/0xaf0 [c000000007287cd0] c000000000628414 do_execveat_common.isra.0+0x1e4/0x310 [c000000007287d80] c00000000062858c sys_execve+0x4c/0x60 [c000000007287db0] c00000000002c1b0 system_call_exception+0x160/0x2c0 [c000000007287e10] c00000000000c53c system_call_common+0xec/0x250

The fix is to make sure we update high_memory on memory hotplug. This is similar to what x86 does in commit 3072e413e305 ("mm/memory_hotplug: introduce add_pages")

Which versions are affected by CVE-2022-49666?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-49666?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2022-49666 being exploited?

There is no known exploitation of CVE-2022-49666 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as DEBIAN-CVE-2022-49666, GHSA-r6x5-vqv8-8gvx, ROOT-OS-DEBIAN-11-CVE-2022-49666, UBUNTU-CVE-2022-49666.