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jpolo1224
4baefed106
Calling sigaction() on Android does not make you the first handler for SIGSEGV. libsigchain intercepts it and runs ART's FaultManager first, which reads the faulting thread's registers as an ArtMethod* and dies on guest data -- so every recoverable guest fault in JIT'd code killed the process before our handler ran, with nothing in the app log to say why. Resolve sigaction from libc directly and install through that, keeping the runtime's previous action so non-emulator faults are forwarded on rather than swallowed. Registering through both paths recurses, so this registers once and guards re-entry. SIGBUS was only handled on Apple platforms; Android raises it for the same unmapped-guest-page cases, so it needs the same treatment. Also make the fault report survive a fault taken while reporting: emit an allocation-free breadcrumb with the signal, address, PC and the GPRs before the formatted dump, and chain to the previous handler first so debuggerd still records a tombstone. The breadcrumb goes after the recovery attempts, not before -- emitting it on entry logged over a thousand recovered faults per second and was itself a stall.