CVE-2025-39903

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 0x0000000000 [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 0x0000000009000000 (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 0x0000000040000000-0x00000000ffffffff]

[ 0.000000] DMA32 empty

[ 0.000000] Normal [mem 0x0000000100000000-0x000000013fffffff]

[ 0.000000] Movable zone start for each node

[ 0.000000] Early memory node ranges

[ 0.000000] node 0: [mem 0x0000000040000000-0x00000000bfffffff]

[ 0.000000] node 1: [mem 0x00000000c0000000-0x000000013fffffff]

[ 0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x00000000bfffffff]

[ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a0

[ 0.000000] Mem abort info:

[ 0.000000] ESR = 0x0000000096000004

[ 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] [00000000000000a0] user address but active_mm is swapper

[ 0.000000] Internal error: Oops: 0000000096000004 [#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: 0000000000000000 x27: 0000000000000000

[ 0.000000] x26: 4ec4ec4ec4ec4ec5 x25: 00000000000c0000 x24: 00000000000c0000

[ 0.000000] x23: 0000000000040000 x22: 0000000000000000 x21: ffffa02ca0f3b368

[ 0.000000] x20: ffffa02ca14c7b98 x19: 0000000000000000 x18: 0000000000000002

[ 0.000000] x17: 000000000000cacc x16: 0000000000000001 x15: 0000000000000001

[ 0.000000] x14: 0000000080000000 x13: 0000000000000018 x12: 0000000000000002

[ 0.0

---truncated---