[rocprofiler-sdk] Fix SIGABRT in construct_agent_cache on WSL2 with DXG backend

[ChrisLundquist]

Summary

• Fix fatal abort in construct_agent_cache() when running on WSL2 with the DXG GPU passthrough backend (HSA_ENABLE_DXG_DETECTION=1)
• When sysfs topology is unavailable, read_topology() returns 0 agents but the HSA runtime discovers agents — the agent count mismatch triggers ROCP_FATAL_IF → SIGABRT
• Add an early-return path that logs a warning instead of crashing, allowing profiling to gracefully degrade
• Add a GTest (agent_no_topology_no_crash) that validates the early-return path

Problem

Any program that triggers rocprofiler-sdk agent enumeration crashes on WSL2:

F agent.cpp:1192] Found 0 rocprofiler agents and 2 HSA agents.
HSA agents contained 2 internal node ids not found by rocprofiler: 0, 1
*** SIGABRT (@0x3e80000e17d) received by PID 57725 ***

This affects rocprofv3 --hip-trace, PyTorch with kineto profiling, and any custom tool using rocprofiler-sdk on WSL2. Also affects containers without /sys mounted.

Root Cause

1. read_topology() reads agents from /sys/class/kfd/kfd/topology/nodes
2. On WSL2 with DXG (or containers), this sysfs path does not exist → returns empty
3. construct_agent_cache() enumerates HSA agents via the runtime (works via DXG, finds CPU + GPU)
4. Agent count mismatch (0 vs 2) hits ROCP_FATAL_IF → abort()

Fix

Before the fatal check, detect when rocprofiler agents are empty (topology unavailable) and return early with a warning. Uses rocp_agents.empty() rather than re-checking the filesystem, which is both simpler and more general.

Test Results (WSL2, AMD RX 9070 XT, ROCm 7.2.1)

New GTest:

[ RUN      ] rocprofiler_lib.agent_no_topology_no_crash
W agent.cpp:608] sysfs nodes path '/sys/class/kfd/kfd/topology/nodes' does not exist
W agent.cpp:1199] rocprofiler agent discovery unavailable (0 rocprofiler agents vs 2 HSA agents). Profiling features will be disabled.
[       OK ] rocprofiler_lib.agent_no_topology_no_crash (24 ms)
[  PASSED  ] 1 test.

End-to-end (before → after):

Test	Before	After
rocprofv3 --hip-trace	SIGABRT (exit 134)	Warning + clean exit (0)
GPU compute kernel under profiler	SIGABRT (exit 134)	Correct result + clean exit (0)
HIP without profiler	Works	Works (no change)
Native Linux (sysfs exists)	Works	No behavioral change

Related

• Previously filed as Fix SIGABRT in construct_agent_cache on WSL2 with DXG backend rocprofiler-sdk#149 (deprecated repo, auto-closed)
• rocprofv3 --pmc crashes with unordered_map::at on systems with iGPU (gfx1036) rocprofiler-sdk#148 (iGPU agent mismatch — same fatal check, different trigger)

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