2025-12-04 15:31:17
Linux
PUBLISHED
In the Linux kernel, the following vulnerability has been resolved:
drm/panthor: Fix kernel panic on partial unmap of a GPU VA region
This commit address a kernel panic issue that can happen if Userspace
tries to partially unmap a GPU virtual region (aka drm_gpuva).
The VM_BIND interface allows partial unmapping of a BO.
Panthor driver pre-allocates memory for the new drm_gpuva structures
that would be needed for the map/unmap operation, done using drm_gpuvm
layer. It expected that only one new drm_gpuva would be needed on umap
but a partial unmap can require 2 new drm_gpuva and thats why it
ended up doing a NULL pointer dereference causing a kernel panic.
Following dump was seen when partial unmap was exercised.
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000078
Mem abort info:
ESR = 0x0000000096000046
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000046, ISS2 = 0x00000000
CM = 0, WnR = 1, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=000000088a863000
[000000000000078] pgd=080000088a842003, p4d=080000088a842003, pud=0800000884bf5003, pmd=0000000000000000
Internal error: Oops: 0000000096000046 [#1] PREEMPT SMP