1 files changed, 50 insertions, 14 deletions

diff --git a/src/syscall/syscall_linux_test.go b/src/syscall/syscall_linux_test.go
index 41ae8cc5a1..adeb7c9ebb 100644
--- a/src/syscall/syscall_linux_test.go
+++ b/src/syscall/syscall_linux_test.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -30,7 +29,7 @@ func chtmpdir(t *testing.T) func() {
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
-	d, err := ioutil.TempDir("", "test")
+	d, err := os.MkdirTemp("", "test")
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
@@ -160,7 +159,7 @@ func TestLinuxDeathSignal(t *testing.T) {
 
 	// Copy the test binary to a location that a non-root user can read/execute
 	// after we drop privileges
-	tempDir, err := ioutil.TempDir("", "TestDeathSignal")
+	tempDir, err := os.MkdirTemp("", "TestDeathSignal")
 	if err != nil {
 		t.Fatalf("cannot create temporary directory: %v", err)
 	}
@@ -321,7 +320,7 @@ func TestSyscallNoError(t *testing.T) {
 
 	// Copy the test binary to a location that a non-root user can read/execute
 	// after we drop privileges
-	tempDir, err := ioutil.TempDir("", "TestSyscallNoError")
+	tempDir, err := os.MkdirTemp("", "TestSyscallNoError")
 	if err != nil {
 		t.Fatalf("cannot create temporary directory: %v", err)
 	}
@@ -543,37 +542,69 @@ func TestAllThreadsSyscall(t *testing.T) {
 func compareStatus(filter, expect string) error {
 	expected := filter + expect
 	pid := syscall.Getpid()
-	fs, err := ioutil.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
+	fs, err := os.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
 	if err != nil {
 		return fmt.Errorf("unable to find %d tasks: %v", pid, err)
 	}
+	expectedProc := fmt.Sprintf("Pid:\t%d", pid)
+	foundAThread := false
 	for _, f := range fs {
 		tf := fmt.Sprintf("/proc/%s/status", f.Name())
-		d, err := ioutil.ReadFile(tf)
-		if os.IsNotExist(err) {
-			// We are racing against threads dying, which
-			// is out of our control, so ignore the
-			// missing file and skip to the next one.
-			continue
-		}
+		d, err := os.ReadFile(tf)
 		if err != nil {
-			return fmt.Errorf("unable to read %q: %v", tf, err)
+			// There are a surprising number of ways this
+			// can error out on linux.  We've seen all of
+			// the following, so treat any error here as
+			// equivalent to the "process is gone":
+			//    os.IsNotExist(err),
+			//    "... : no such process",
+			//    "... : bad file descriptor.
+			continue
 		}
 		lines := strings.Split(string(d), "\n")
 		for _, line := range lines {
 			// Different kernel vintages pad differently.
 			line = strings.TrimSpace(line)
+			if strings.HasPrefix(line, "Pid:\t") {
+				// On loaded systems, it is possible
+				// for a TID to be reused really
+				// quickly. As such, we need to
+				// validate that the thread status
+				// info we just read is a task of the
+				// same process PID as we are
+				// currently running, and not a
+				// recently terminated thread
+				// resurfaced in a different process.
+				if line != expectedProc {
+					break
+				}
+				// Fall through in the unlikely case
+				// that filter at some point is
+				// "Pid:\t".
+			}
 			if strings.HasPrefix(line, filter) {
 				if line != expected {
-					return fmt.Errorf("%q got:%q want:%q (bad)\n", tf, line, expected)
+					return fmt.Errorf("%q got:%q want:%q (bad) [pid=%d file:'%s' %v]\n", tf, line, expected, pid, string(d), expectedProc)
 				}
+				foundAThread = true
 				break
 			}
 		}
 	}
+	if !foundAThread {
+		return fmt.Errorf("found no thread /proc/<TID>/status files for process %q", expectedProc)
+	}
 	return nil
 }
 
+// killAThread locks the goroutine to an OS thread and exits; this
+// causes an OS thread to terminate.
+func killAThread(c <-chan struct{}) {
+	runtime.LockOSThread()
+	<-c
+	return
+}
+
 // TestSetuidEtc performs tests on all of the wrapped system calls
 // that mirror to the 9 glibc syscalls with POSIX semantics. The test
 // here is considered authoritative and should compile and run
@@ -624,6 +655,11 @@ func TestSetuidEtc(t *testing.T) {
 	}
 
 	for i, v := range vs {
+		// Generate some thread churn as we execute the tests.
+		c := make(chan struct{})
+		go killAThread(c)
+		close(c)
+
 		if err := v.fn(); err != nil {
 			t.Errorf("[%d] %q failed: %v", i, v.call, err)
 			continue