Fix race build error.

This adds a test to smoke-tests to ensure that the race build does not
break again. In debugging this issue, a race in the nogo tool itself
was discovered, and a related fix is included.

PiperOrigin-RevId: 424393624

Makefile

@@ -187,6 +187,7 @@ debian: ## Builds the debian packages.
 
 smoke-tests: ## Runs a simple smoke test after build runsc.
 	@$(call run,//runsc,--alsologtostderr --network none --debug --TESTONLY-unsafe-nonroot=true --rootless do true)
+	@$(call run,$(RACE_FLAGS) //runsc:runsc-race,--alsologtostderr --network none --debug --TESTONLY-unsafe-nonroot=true --rootless do true)
 .PHONY: smoke-tests
 
 nogo-tests:

tools/bazel.mk

@@ -40,6 +40,7 @@ BRANCH_NAME := $(shell (git branch --show-current 2>/dev/null || \
   git rev-parse --abbrev-ref HEAD 2>/dev/null) | \
   xargs -n 1 basename 2>/dev/null)
 BUILD_ROOTS := bazel-bin/ bazel-out/
+RACE_FLAGS := --@io_bazel_rules_go//go/config:race
 
 # Bazel container configuration (see below).
 USER := $(shell whoami)

tools/bazeldefs/defs.bzl

@@ -34,6 +34,7 @@ def select_system(linux = ["__linux__"], darwin = [], **kwargs):
     })
 
 arch_config = [
+    "@io_bazel_rules_go//go/config:race",
     "//command_line_option:cpu",
     "//command_line_option:crosstool_top",
     "//command_line_option:platforms",
@@ -41,6 +42,9 @@ arch_config = [
 
 def arm64_config(settings, attr):
     return {
+        # Race builds are always disabled for cross-architecture generation. We
+        # can't run it locally anyways, what value can this provide?
+        "@io_bazel_rules_go//go/config:race": False,
         "//command_line_option:cpu": "aarch64",
         "//command_line_option:crosstool_top": "@crosstool//:toolchains",
         "//command_line_option:platforms": "@io_bazel_rules_go//go/toolchain:linux_arm64",
@@ -48,6 +52,8 @@ def arm64_config(settings, attr):
 
 def amd64_config(settings, attr):
     return {
+        # See above.
+        "@io_bazel_rules_go//go/config:race": False,
         "//command_line_option:cpu": "k8",
         "//command_line_option:crosstool_top": "@crosstool//:toolchains",
         "//command_line_option:platforms": "@io_bazel_rules_go//go/toolchain:linux_amd64",

tools/nogo/defs.bzl

@@ -112,7 +112,7 @@ nogo_stdlib = go_rule(
     attrs = {
         "_nogo": attr.label(
             default = "//tools/nogo:nogo",
-            cfg = "host",
+            cfg = "exec",
         ),
         "_target": attr.label(
             default = "//tools/nogo:target",
@@ -319,7 +319,7 @@ nogo_aspect = go_rule(
     attrs = {
         "_nogo": attr.label(
             default = "//tools/nogo:nogo",
-            cfg = "host",
+            cfg = "exec",
         ),
         "_target": attr.label(
             default = "//tools/nogo:target",
@@ -329,7 +329,7 @@ nogo_aspect = go_rule(
         # appears to be reserved for some internal bazel use.
         "_nogo_stdlib": attr.label(
             default = "//tools/nogo:stdlib",
-            cfg = "host",
+            cfg = "target",
         ),
     },
 )
@@ -411,7 +411,7 @@ nogo_test = rule(
         ),
         "_nogo": attr.label(
             default = "//tools/nogo:nogo",
-            cfg = "host",
+            cfg = "exec",
         ),
         "_target": attr.label(
             default = "//tools/nogo:target",
@@ -493,12 +493,12 @@ nogo_facts = go_rule(
         ),
         "_nogo": attr.label(
             default = "//tools/nogo:nogo",
-            cfg = "host",
+            cfg = "exec",
         ),
         # See _nogo_aspect, above.
         "_nogo_stdlib": attr.label(
             default = "//tools/nogo:stdlib",
-            cfg = "host",
+            cfg = "target",
         ),
         "_target": attr.label(
             default = "//tools/nogo:target",

tools/worker/worker.go

@@ -32,7 +32,6 @@ import (
 	"sort"
 	"strings"
 	"sync"
-	"time"
 
 	_ "net/http/pprof" // For profiling.
 
@@ -243,6 +242,19 @@ func allCacheStats() string {
 	return sb.String()
 }
 
+// safeBuffer is a trivial wrapper around bytes.Buffer.
+type safeBuffer struct {
+	mu sync.Mutex
+	bytes.Buffer
+}
+
+// Write implements io.Writer.Write.
+func (s *safeBuffer) Write(p []byte) (int, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.Buffer.Write(p)
+}
+
 // Work invokes the main function.
 func Work(run func([]string) int) {
 	flag.CommandLine.Parse(os.Args[1:])
@@ -298,8 +310,6 @@ func Work(run func([]string) int) {
 			log.Fatalf("unable to move stdout: %v", err)
 		}
 	}
-
-	// Best-effort: collect logs.
 	rPipe, wPipe, err := os.Pipe()
 	if err != nil {
 		log.Fatalf("unable to create pipe: %v", err)
@@ -310,8 +320,8 @@ func Work(run func([]string) int) {
 	if err := unix.Dup2(int(wPipe.Fd()), 2); err != nil {
 		log.Fatalf("error duping over stderr: %v", err)
 	}
-	wPipe.Close()
-	defer rPipe.Close()
+	wPipe.Close() // Still open at stdout, stderr.
+	rPipe.Close() // Read end of pipe is now closed.
 
 	// Read requests from stdin.
 	input := bufio.NewReader(os.NewFile(0, "input"))
@@ -348,30 +358,16 @@ func Work(run func([]string) int) {
 		}
 
 		// Prepare logging.
-		outputBuffer := bytes.NewBuffer(nil)
+		var outputBuffer safeBuffer
 		outputBuffer.WriteString(listenHeader)
-		log.SetOutput(outputBuffer)
+		log.SetOutput(&outputBuffer)
 
 		// Parse all arguments.
 		flag.CommandLine.Parse(wreq.GetArguments())
-		var exitCode int
-		exitChan := make(chan int)
-		go func() { exitChan <- run(flag.CommandLine.Args()) }()
-		for running := true; running; {
-			select {
-			case exitCode = <-exitChan:
-				running = false
-			default:
-			}
-			// N.B. rPipe is given a read deadline of 1ms. We expect
-			// this to turn a copy error after 1ms, and we just keep
-			// flushing this buffer while the task is running.
-			rPipe.SetReadDeadline(time.Now().Add(time.Millisecond))
-			outputBuffer.ReadFrom(rPipe)
-		}
+		exitCode := run(flag.CommandLine.Args())
 
+		// Attach all cache stats.
 		if *workerDebug {
-			// Attach all cache stats.
 			outputBuffer.WriteString(allCacheStats())
 		}