[BUG] gpu: drm: amdgpu: Possible sleep-in-atomic-context bugs in amdgpu_uvd_ring_begin_use()

* [BUG] gpu: drm: amdgpu: Possible sleep-in-atomic-context bugs in amdgpu_uvd_ring_begin_use()
@ 2018-09-15  8:59 Jia-Ju Bai
  0 siblings, 0 replies; only message in thread
From: Jia-Ju Bai @ 2018-09-15  8:59 UTC (permalink / raw)
  To: alexander.deucher, christian.koenig, David1.Zhou, airlied
  Cc: amd-gfx, dri-devel, Linux Kernel Mailing List

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

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