From 6b83111499e9a8f42b6aa3998839922ba70eefdc Mon Sep 17 00:00:00 2001 From: Ian Gudger Date: Fri, 10 Jan 2020 13:33:12 -0800 Subject: [PATCH] goid: new package Allows retrieving the goroutine ID for concurrency testing when the race detector is enabled. Updates #1472 PiperOrigin-RevId: 289155308 --- pkg/goid/BUILD | 26 +++++++++++++++ pkg/goid/empty_test.go | 22 ++++++++++++ pkg/goid/goid.go | 24 +++++++++++++ pkg/goid/goid_amd64.s | 21 ++++++++++++ pkg/goid/goid_race.go | 25 ++++++++++++++ pkg/goid/goid_test.go | 74 +++++++++++++++++++++++++++++++++++++++++ pkg/goid/goid_unsafe.go | 64 +++++++++++++++++++++++++++++++++++ 7 files changed, 256 insertions(+) create mode 100644 pkg/goid/BUILD create mode 100644 pkg/goid/empty_test.go create mode 100644 pkg/goid/goid.go create mode 100644 pkg/goid/goid_amd64.s create mode 100644 pkg/goid/goid_race.go create mode 100644 pkg/goid/goid_test.go create mode 100644 pkg/goid/goid_unsafe.go diff --git a/pkg/goid/BUILD b/pkg/goid/BUILD new file mode 100644 index 000000000..5d31e5366 --- /dev/null +++ b/pkg/goid/BUILD @@ -0,0 +1,26 @@ +load("//tools/go_stateify:defs.bzl", "go_library") +load("@io_bazel_rules_go//go:def.bzl", "go_test") + +package(licenses = ["notice"]) + +go_library( + name = "goid", + srcs = [ + "goid.go", + "goid_amd64.s", + "goid_race.go", + "goid_unsafe.go", + ], + importpath = "gvisor.dev/gvisor/pkg/goid", + visibility = ["//visibility:public"], +) + +go_test( + name = "goid_test", + size = "small", + srcs = [ + "empty_test.go", + "goid_test.go", + ], + embed = [":goid"], +) diff --git a/pkg/goid/empty_test.go b/pkg/goid/empty_test.go new file mode 100644 index 000000000..c0a4b17ab --- /dev/null +++ b/pkg/goid/empty_test.go @@ -0,0 +1,22 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build !race + +package goid + +import "testing" + +// TestNothing exists to make the build system happy. +func TestNothing(t *testing.T) {} diff --git a/pkg/goid/goid.go b/pkg/goid/goid.go new file mode 100644 index 000000000..39df30031 --- /dev/null +++ b/pkg/goid/goid.go @@ -0,0 +1,24 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build !race + +// Package goid provides access to the ID of the current goroutine in +// race/gotsan builds. +package goid + +// Get returns the ID of the current goroutine. +func Get() int64 { + panic("unimplemented for non-race builds") +} diff --git a/pkg/goid/goid_amd64.s b/pkg/goid/goid_amd64.s new file mode 100644 index 000000000..d9f5cd2a3 --- /dev/null +++ b/pkg/goid/goid_amd64.s @@ -0,0 +1,21 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "textflag.h" + +// func getg() *g +TEXT ·getg(SB),NOSPLIT,$0-8 + MOVQ (TLS), R14 + MOVQ R14, ret+0(FP) + RET diff --git a/pkg/goid/goid_race.go b/pkg/goid/goid_race.go new file mode 100644 index 000000000..1766beaee --- /dev/null +++ b/pkg/goid/goid_race.go @@ -0,0 +1,25 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Only available in race/gotsan builds. +// +build race + +// Package goid provides access to the ID of the current goroutine in +// race/gotsan builds. +package goid + +// Get returns the ID of the current goroutine. +func Get() int64 { + return goid() +} diff --git a/pkg/goid/goid_test.go b/pkg/goid/goid_test.go new file mode 100644 index 000000000..31970ce79 --- /dev/null +++ b/pkg/goid/goid_test.go @@ -0,0 +1,74 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build race + +package goid + +import ( + "runtime" + "sync" + "testing" +) + +func TestInitialGoID(t *testing.T) { + const max = 10000 + if id := goid(); id < 0 || id > max { + t.Errorf("got goid = %d, want 0 < goid <= %d", id, max) + } +} + +// TestGoIDSquence verifies that goid returns values which could plausibly be +// goroutine IDs. If this test breaks or becomes flaky, the structs in +// goid_unsafe.go may need to be updated. +func TestGoIDSquence(t *testing.T) { + // Goroutine IDs are cached by each P. + runtime.GOMAXPROCS(1) + + // Fill any holes in lower range. + for i := 0; i < 50; i++ { + var wg sync.WaitGroup + wg.Add(1) + go func() { + wg.Done() + + // Leak the goroutine to prevent the ID from being + // reused. + select {} + }() + wg.Wait() + } + + id := goid() + for i := 0; i < 100; i++ { + var ( + newID int64 + wg sync.WaitGroup + ) + wg.Add(1) + go func() { + newID = goid() + wg.Done() + + // Leak the goroutine to prevent the ID from being + // reused. + select {} + }() + wg.Wait() + if max := id + 100; newID <= id || newID > max { + t.Errorf("unexpected goroutine ID pattern, got goid = %d, want %d < goid <= %d (previous = %d)", newID, id, max, id) + } + id = newID + } +} diff --git a/pkg/goid/goid_unsafe.go b/pkg/goid/goid_unsafe.go new file mode 100644 index 000000000..ded8004dd --- /dev/null +++ b/pkg/goid/goid_unsafe.go @@ -0,0 +1,64 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package goid + +// Structs from Go runtime. These may change in the future and require +// updating. These structs are currently the same on both AMD64 and ARM64, +// but may diverge in the future. + +type stack struct { + lo uintptr + hi uintptr +} + +type gobuf struct { + sp uintptr + pc uintptr + g uintptr + ctxt uintptr + ret uint64 + lr uintptr + bp uintptr +} + +type g struct { + stack stack + stackguard0 uintptr + stackguard1 uintptr + + _panic uintptr + _defer uintptr + m uintptr + sched gobuf + syscallsp uintptr + syscallpc uintptr + stktopsp uintptr + param uintptr + atomicstatus uint32 + stackLock uint32 + goid int64 + + // More fields... + // + // We only use goid and the fields before it are only listed to + // calculate the correct offset. +} + +func getg() *g + +// goid returns the ID of the current goroutine. +func goid() int64 { + return getg().goid +}