The driver may sleep with holding a spinlock. The function call paths (from bottom to top) in Linux-4.17 are:
[FUNC] mutex_lock_nested drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477: mutex_lock_nested in amdgpu_dpm_enable_uvd drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154: amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80: [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199: amdgpu_ring_alloc in amdgpu_virt_kiq_wreg drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207: amdgpu_virt_kiq_wreg in amdgpu_mm_wreg drivers/gpu/drm/amd/amdgpu/vi.c, 207: amdgpu_mm_wreg in vi_gc_cac_rreg drivers/gpu/drm/amd/amdgpu/vi.c, 206: _raw_spin_lock_irqsave in vi_gc_cac_rreg
[FUNC] mutex_lock_nested drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477: mutex_lock_nested in amdgpu_dpm_enable_uvd drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154: amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80: [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199: amdgpu_ring_alloc in amdgpu_virt_kiq_wreg drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207: amdgpu_virt_kiq_wreg in amdgpu_mm_wreg drivers/gpu/drm/amd/amdgpu/soc15.c, 106: amdgpu_mm_wreg in soc15_pcie_rreg drivers/gpu/drm/amd/amdgpu/soc15.c, 105: _raw_spin_lock_irqsave in soc15_pcie_rreg
[FUNC] mutex_lock_nested drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477: mutex_lock_nested in amdgpu_dpm_enable_uvd drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154: amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80: [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199: amdgpu_ring_alloc in amdgpu_virt_kiq_wreg drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207: amdgpu_virt_kiq_wreg in amdgpu_mm_wreg drivers/gpu/drm/amd/amdgpu/cik.c, 139: amdgpu_mm_wreg in cik_uvd_ctx_wreg drivers/gpu/drm/amd/amdgpu/cik.c, 138: _raw_spin_lock_irqsave in cik_uvd_ctx_wreg
[FUNC] mutex_lock_nested drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477: mutex_lock_nested in amdgpu_dpm_enable_uvd drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154: amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80: [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199: amdgpu_ring_alloc in amdgpu_virt_kiq_wreg drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207: amdgpu_virt_kiq_wreg in amdgpu_mm_wreg drivers/gpu/drm/amd/amdgpu/dce_v6_0.c, 126: amdgpu_mm_wreg in dce_v6_0_audio_endpt_rreg drivers/gpu/drm/amd/amdgpu/dce_v6_0.c, 125: _raw_spin_lock_irqsave in dce_v6_0_audio_endpt_rreg
Note that [FUNC_PTR] means a function pointer call is used.
These bugs are found by my static analysis tool DSAC.
Best wishes, Jia-Ju Bai