drm/amdkfd: Reject zero-sized AQL queue allocations after size halving

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KFD_IOC_ALLOC_MEMORY_OF_GPU with flag
KFD_IOC_ALLOC_MEM_FLAGS_AQL_QUEUE_MEM and size=1 triggers the AQL
wraparound workaround (size >>= 1), reducing size to 0. The resulting
zero passes through PAGE_ALIGN(0) = 0 without validation, bypassing the
per-process VRAM quota check in reserve_mem_limit()
(vram_used + 0 > vram_available is always false).

The fix adds post-halving zero-size validation in the primary
allocation path (amdgpu_amdkfd_gpuvm.c). The check happens after size
halving but before reserve_mem_limit(), and uses err_alignment_size
error path to properly clean up the allocated kgd_mem structure and
mutex.

Cc: stable@vger.kernel.org
Signed-off-by: Sunday Clement <Sunday.Clement@amd.com>
Reviewed-by: Alex Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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Sunday Clement 2026-08-06 10:59:34 -04:00 • committed by Alex Deucher

parent 2ee9836545

commit 40ba09e111

2 changed files with 9 additions and 1 deletions

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7

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c

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3

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

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