internal/testsuite: lock tracer thread

This avoids getting the goroutine preempted and scheduled onto a
thread other than the tracer.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 4 insertions, 0 deletions

diff --git a/internal/testsuite/ptrace.go b/internal/testsuite/ptrace.go
index b35816ec..d7abd0aa 100644
--- a/internal/testsuite/ptrace.go
+++ b/internal/testsuite/ptrace.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"runtime"
 	"syscall"
 	"unsafe"
 )
@@ -113,6 +114,9 @@ func getFilter(pid, index int) ([]syscall.SockFilter, error) {
 // CheckFilter checks the process at pid to have its first filter's contents
 // match the specified sha512 checksum.
 func CheckFilter(pid, index int, sum [sha512.Size]byte) (err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	if err = ptraceAttach(pid); err != nil {
 		return
 	}