Current mainline git (24e700e291d52bd2) hangs when building software concurrently (for example perf). The issue is not 100% reproducible (sometimes building perf succeeds), so bisecting will not work. Magic SysRq key doesn't work and there is nothing in the logs. Enabling CONFIG_PROVE_LOCKING makes the issue go away.
Any ideas on how to debug this further? -- Markus
