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drm: Account property blob allocations to memcg

DRM_IOCTL_MODE_CREATEPROPBLOB allows userspace to allocate arbitrary-sized
property blobs backed by kernel memory.

Currently, the blob data allocation is not accounted to the allocating
process's memory cgroup, allowing unprivileged users to trigger unbounded
kernel memory consumption and potentially cause system-wide OOM.

Mark the property blob data allocation with GFP_KERNEL_ACCOUNT so that the memory
is properly charged to the caller's memcg. This ensures existing cgroup
memory limits apply and prevents uncontrolled kernel memory growth without
introducing additional policy or per-file limits.

Signed-off-by: Xiao Kan <814091656@qq.com>
Signed-off-by: Xiao Kan <xiao.kan@samsung.com>
Link: https://patch.msgid.link/tencent_D12AA2DEDE6F359E1AF59405242FB7A5FD05@qq.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>

authored by

Xiao Kan and committed by
Maxime Ripard 26b4309a 64aa8b3a

+1 -1
+1 -1
drivers/gpu/drm/drm_property.c
··· 562 562 if (!length || length > INT_MAX - sizeof(struct drm_property_blob)) 563 563 return ERR_PTR(-EINVAL); 564 564 565 - blob = kvzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL); 565 + blob = kvzalloc(sizeof(struct drm_property_blob) + length, GFP_KERNEL_ACCOUNT); 566 566 if (!blob) 567 567 return ERR_PTR(-ENOMEM); 568 568