[PATCH for 4.9 17/39] MIPS: IRQ Stack: Unwind IRQ stack onto task stack

From: Matt Redfearn [ Upstream commit db8466c581cca1a08b505f1319c3ecd246f16fa8 ] When the separate IRQ stack was introduced, stack unwinding only proceeded as far as the top of the IRQ stack, leading to kernel backtraces being less useful, lacking the trace of what was

[PATCH for 4.9 17/39] MIPS: IRQ Stack: Unwind IRQ stack onto task stack

From: Matt Redfearn [ Upstream commit db8466c581cca1a08b505f1319c3ecd246f16fa8 ] When the separate IRQ stack was introduced, stack unwinding only proceeded as far as the top of the IRQ stack, leading to kernel backtraces being less useful, lacking the trace of what was interrupted. Fix this by