CVE: CVE-2025-39903
Published: 2025-10-01
Description: In the Linux kernel, the following vulnerability has been resolved:

of_numa: fix uninitialized memory nodes causing kernel panic

When there are memory-only nodes (nodes without CPUs), these nodes are not
properly initialized, causing kernel panic during boot.

of_numa_init
	of_numa_parse_cpu_nodes
		node_set(nid, numa_nodes_parsed);
	of_numa_parse_memory_nodes

In of_numa_parse_cpu_nodes, numa_nodes_parsed gets updated only for nodes
containing CPUs.  Memory-only nodes should have been updated in
of_numa_parse_memory_nodes, but they weren't.

Subsequently, when free_area_init() attempts to access NODE_DATA() for
these uninitialized memory nodes, the kernel panics due to NULL pointer
dereference.

This can be reproduced on ARM64 QEMU with 1 CPU and 2 memory nodes:

qemu-system-aarch64 \
-cpu host -nographic \
-m 4G -smp 1 \
-machine virt,accel=kvm,gic-version=3,iommu=smmuv3 \
-object memory-backend-ram,size=2G,id=mem0 \
-object memory-backend-ram,size=2G,id=mem1 \
-numa node,nodeid=0,memdev=mem0 \
-numa node,nodeid=1,memdev=mem1 \
-kernel $IMAGE \
-hda $DISK \
-append "console=ttyAMA0 root=/dev/vda rw earlycon"

[    0.000000] Booting Linux on physical CPU 0x[PII_REDACTED] [0x481fd010]
[    0.000000] Linux version 6.17.0-rc1-00001-gabb4b3daf18c-dirty (yintirui@local) (gcc (GCC) 12.3.1, GNU ld (GNU Binutils) 2.41) #52 SMP PREEMPT Mon Aug 18 09:49:40 CST 2025
[    0.000000] KASLR enabled
[    0.000000] random: crng init done
[    0.000000] Machine model: linux,dummy-virt
[    0.000000] efi: UEFI not found.
[    0.000000] earlycon: pl11 at MMIO 0x[PII_REDACTED]000000 (options '')
[    0.000000] printk: legacy bootconsole [pl11] enabled
[    0.000000] OF: reserved mem: Reserved memory: No reserved-memory node in the DT
[    0.000000] NODE_DATA(0) allocated [mem 0xbfffd9c0-0xbfffffff]
[    0.000000] node 1 must be removed before remove section 23
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x[PII_REDACTED]000000-0x00000000ffffffff]
[    0.000000]   DMA32    empty
[    0.000000]   Normal   [mem 0x[PII_REDACTED]000000-0x000000013fffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x[PII_REDACTED]000000-0x00000000bfffffff]
[    0.000000]   node   1: [mem 0x00000000c0000000-0x000000013fffffff]
[    0.000000] Initmem setup node 0 [mem 0x[PII_REDACTED]000000-0x00000000bfffffff]
[    0.000000] Unable to handle kernel NULL pointer dereference at virtual address[PII_REDACTED]0000a0
[    0.000000] Mem abort info:
[    0.000000]   ESR = 0x[PII_REDACTED]000004
[    0.000000]   EC = 0x25: DABT (current EL), IL = 32 bits
[    0.000000]   SET = 0, FnV = 0
[    0.000000]   EA = 0, S1PTW = 0
[    0.000000]   FSC = 0x04: level 0 translation fault
[    0.000000] Data abort info:
[    0.000000]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[    0.000000]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[    0.000000]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[    0.000000] [[PII_REDACTED]0000a0] user address but active_mm is swapper
[    0.000000] Internal error: Oops: [PII_REDACTED] [#1]  SMP
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.17.0-rc1-00001-g760c6dabf762-dirty #54 PREEMPT
[    0.000000] Hardware name: linux,dummy-virt (DT)
[    0.000000] pstate: 800000c5 (Nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[    0.000000] pc : free_area_init+0x50c/0xf9c
[    0.000000] lr : free_area_init+0x5c0/0xf9c
[    0.000000] sp : ffffa02ca0f33c00
[    0.000000] x29: ffffa02ca0f33cb0 x28: [PII_REDACTED] x27: [PII_REDACTED]
[    0.000000] x26: 4ec4ec4ec4ec4ec5 x25:[PII_REDACTED]0c0000 x24:[PII_REDACTED]0c0000
[    0.000000] x23: [PII_REDACTED] x22: [PII_REDACTED] x21: ffffa02ca0f3b368
[    0.000000] x20: ffffa02ca14c7b98 x19: [PII_REDACTED] x18: [PII_REDACTED]
[    0.000000] x17:[PII_REDACTED]00cacc x16: [PII_REDACTED] x15: [PII_REDACTED]
[    0.000000] x14: [PII_REDACTED] x13: [PII_REDACTED] x12: [PII_REDACTED]
[    0.0
---truncated---
CVSS Score: 5.5 (MEDIUM)
CWE: CWE-476, CWE-476
References: https://git.kernel.org/stable/c/c2daa6eb4740720b5bd0e06267d7c93a3eed844e; https://git.kernel.org/stable/c/ee4d098cbc9160f573b5c1b5a51d6158efdb2896; https://git.kernel.org/stable/c/f3286ad8eeae15fd4bd5c12f9adfe888b26baf62