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docs/drivers/amd/hang-debugging.rst

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+
+.. _radv-debug-hang:
+
+Debugging GPU hangs with RADV
+=============================
+
+UMR (optional)
+--------------
+
+UMR is needed for dumping a lot of useful information. Clone, build and install
+`UMR <https://gitlab.freedesktop.org/tomstdenis/umr>`__. Do not forget to run
+``chmod +s $(which umr)`` so RADV can actually access UMR.
+
+UMR needs to access some kernel debug interfaces:
+
+.. code-block:: sh
+
+   chmod 777 /sys/kernel/debug
+   chmod -R 777 /sys/kernel/debug/dri
+
+Secure boot has to be disabled as well.
+
+Generating and analyzing hang reports
+-------------------------------------
+
+With UMR installed, you can now set ``RADV_DEBUG=hang`` which makes RADV insert
+trace markers and synchronization and check for hangs. The hang report will be
+saved to ``~/radv_dumps_<pid>_<time>``. Inside the directory of the hang report,
+there are a couple of files:
+
+* ``*.spv``: SPIR-V binaries of the pipeline that was bound when the hang
+  occurred.
+* ``addr_binding_report.log``: VK_EXT_address_binding_report logs.
+* ``app_info.log``: ``VkApplicationInfo`` fields.
+* ``bo_history.log``: A list of every GPU memory allocation and deallocation.
+  If the GPU hang was caused by a page fault, you can use
+  `radv_check_va.py <https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/src/amd/vulkan/tools/radv_check_va.py>`__
+  to figure out if address is invalid or used after the memory was deallocated.
+* ``bo_ranges.log``: Address ranges that were valid at the time of submission.
+* ``dmesg.log``: Output of ``dmesg``, if available.
+* ``gpu_info.log``: Fields of ``radeon_info``.
+* ``pipeline.log``: IR of the shaders that were bound during the hang as well as
+  programm counters of waves executing said shaders and bound descriptors.
+* ``registers.log``: Various GPU state registers.
+* ``trace.log``: An annotated list of the command stream that caused the hang.
+  the commands that hung come after
+  ``!!!!! This is the last trace point that was reached by the CP !!!!!``.
+* ``umr_ring.log``: Similar to ``trace.log``.
+* ``umr_waves.log``: A list of waves that were active at the time of the hang,
+  including register values.
+* ``vm_fault.log``: The page fault address if a page fault occurred.
+
+Note: By default, the backend IR (ACO or LLVM) and the disassembly should be
+dumped to ``pipeline.log``. But due to shaders caching, you might need
+``RADV_DEBUG=hang,nocache`` to get SPIR-V and NIR in the GPU hang report.
+
+Debugging Steam games
+---------------------
+
+Steam games require a bit more work so RADV can access UMR: In your Steam library,
+make sure **Tools** is checked and search for **Steam Linux Runtime**.
+Under **Properties** -> **Installed Files**, click **Browse**, open
+``_v2-entry-point`` and add
+
+.. code-block:: sh
+
+   shift 2
+   exec "$@"
+
+at the top of the file. Hang debugging can be enabled by selecting the faulting
+game and adding ``RADV_DEBUG=hang %command%`` under **Properties** -> **General**
+-> **LAUNCH OPTIONS**.
+
+Debugging hangs without RADV_DEBUG=hang
+---------------------------------------
+
+In some situations, ``RADV_DEBUG=hang`` wouldn't be able to generate a GPU hang
+report, like for synchronization issues (because it enables
+``RADV_DEBUG=syncshaders`` behind the scene). An alternative solution is to
+disable GPU recovery by adding ``amdgpu.gpu_recovery=0`` to your kernel command
+line options. And then invoke UMR manually with
+``umr --by-pci <pci_id> -O bits,halt_waves -go 0 -wa <ring> -go 1 2>&1`` for
+dumping the waves and ``umr --by-pci <pci_id> -RS <ring> 2>&1`` for dumping the
+rings once the GPU hang occurred.