Repository: go
Issue: runtime: crash on `linux-riscv64-jsing` during bootstrap
Labels: Builders,NeedsInvestigation,compiler/runtime

[2022-06-27T14:35:57-a861eee/linux-riscv64-jsing](https://build.golang.org/log/ebbcc478cc5607e8d40703a43194159d7d523dbb):

```
Building Go toolchain1 using /usr/local/goboot.
# bootstrap/cmd/internal/obj/wasm
unexpected fault address 0xfffffff1b4ca8b09
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x1 addr=0xfffffff1b4ca8b09 pc=0x2c488c]

goroutine 9 [running]:
runtime.throw(0x87f47f, 0x5)
	/home/joel/src/go/src/runtime/panic.go:1117 +0x64 fp=0x3fbccd7350 sp=0x3fbccd7328 pc=0x4a8ec
runtime.sigpanic()
	/home/joel/src/go/src/runtime/signal_unix.go:741 +0x2b8 fp=0x3fbccd7380 sp=0x3fbccd7350 pc=0x63dd8
runtime: unexpected return pc for cmd/compile/internal/ssa.(*regAllocState).allocValToReg called from 0x3fbcb0d7f8
stack: frame={sp:0x3fbccd7388, fp:0x3fbccd7408} stack=[0x3fbcccc000,0x3fbccdc000)
0000003fbccd7288:  000000000004c278 <runtime.gwrite+64>  0000000000e2ee0b 
0000003fbccd7298:  00000000008ae228  0000000000000001 
0000003fbccd72a8:  0000000000000001  0000000000000000 
0000003fbccd72b8:  000000000004cb78 <runtime.printstring+104>  0000000000000002 
0000003fbccd72c8:  00000000008ae228  0000000000000001 
0000003fbccd72d8:  0000000000000001  0000000000000012 
0000003fbccd72e8:  0000000000000019  000000000004aa9c <runtime.fatalthrow+76> 
0000003fbccd72f8:  000000000004a8ec <runtime.throw+100>  0000003fbccd7308 
0000003fbccd7308:  000000000007bcf8 <runtime.fatalthrow.func1+0>  0000003fbc083500 
0000003fbccd7318:  000000000004a8ec <runtime.throw+100>  0000003fbccd7328 
0000003fbccd7328:  0000000000063dd8 <runtime.sigpanic+696>  0000003fbccd7338 
0000003fbccd7338:  000000000007bc70 <runtime.throw.func1+0>  000000000087f47f 
0000003fbccd7348:  0000000000000005  00000000002c488c <cmd/compile/internal/ssa.(*regAllocState).allocValToReg+436> 
0000003fbccd7358:  000000000087f47f  0000000000000005 
0000003fbccd7368:  0000000000000000  fffffff1b4ca8b09 
0000003fbccd7378:  0000003fbc083500  00000000002c4cb0 <cmd/compile/internal/ssa.(*regAllocState).allocValToReg+1496> 
0000003fbccd7388: <0000003fbcb0d7f8  00000000002c9c84 <cmd/compile/internal/ssa.(*regAllocState).regalloc+12316> 
0000003fbccd7398:  0000003fbc7a5c80  0000000000000200 
0000003fbccd73a8:  0000003fbca69e09  0000003fbc984038 
0000003fbccd73b8:  00000000002c6ab4 <cmd/compile/internal/ssa.(*regAllocState).advanceUses+276>  0000003fbc414420 
0000003fbccd73c8:  0000000000090028 <strconv.(*extFloat).FixedDecimal+800>  002ed202000a7000 
0000003fbccd73d8:  00000000002c9bac <cmd/compile/internal/ssa.(*regAllocState).regalloc+12100>  03f79d71b4ca8b09 
0000003fbccd73e8:  0000003fbd11db00  0000003fbc984038 
0000003fbccd73f8:  0000003fbd13a000  0000003fbc984038 
0000003fbccd7408: >0000000000000003  00000000002c30dc <cmd/compile/internal/ssa.regalloc+100> 
0000003fbccd7418:  0000003fbc7a5c80  0000003fbca69ea0 
0000003fbccd7428:  0000000000000200  00000004bcb0d501 
0000003fbccd7438:  00000000002ed200 <cmd/compile/internal/ssa.rewriteValue386_Op386MOVBstore+2768>  0000003fbc984038 
0000003fbccd7448:  0000000000000004  0000000000000008 
0000003fbccd7458:  0000003fbcee4000  00000000000001c3 
0000003fbccd7468:  00050800000001c3  ffff0001bca5e500 
0000003fbccd7478:  0000000000000571  00000000ffffffff 
0000003fbccd7488:  ffffffffffffff09  00000e0abca5e500 
0000003fbccd7498:  0000000000000002  0000000000000000 
0000003fbccd74a8:  0000000000000002  00000000000001c3 
0000003fbccd74b8:  0000003fbca5e280  0000000000000000 
0000003fbccd74c8:  0000000000000006  ffffffffffffffff 
0000003fbccd74d8:  0000000000000004  0000000000000000 
0000003fbccd74e8:  000000000000000a  0000000000000104 
0000003fbccd74f8:  0000000000000003  0000000000000010 
cmd/compile/internal/ssa.(*regAllocState).allocValToReg(0x2c30dc, 0x3fbc7a5c80, 0x3fbca69ea0, 0x200, 0x4bcb0d501, 0x2ed200)
	/home/joel/src/go/src/cmd/compile/internal/ssa/regalloc.go:501 +0x1b4 fp=0x3fbccd7408 sp=0x3fbccd7388 pc=0x2c488c
created by cmd/compile/internal/gc.compileFunctions
	/home/joel/src/go/src/cmd/compile/internal/gc/pgen.go:382 +0x134
```

Perhaps the bootstrap Go version needs to be updated to fix some known bug?

cc @golang/riscv64 @golang/runtime