I also traced in gdb, and execution winds up in a tight loop on:
(gdb) stepi
63 j .LRISCV_Exception_handler
(gdb) stepi
67 addi sp, sp, -CPU_INTERRUPT_FRAME_SIZE
(gdb)
_RISCV_Vector_table ()
at ../../../cpukit/score/cpu/riscv/riscv-exception-handler.S:70
70 SREG a0, RISCV_INTERRUPT_FRAME_A0(sp)
(gdb)
63 j .LRISCV_Exception_handler
So this seems quite like a problem of spurious interrupt, probably the timer configuration is wrong in 32-bit risc-v after the bad commit.