proc: disable asyncpreempt on linux/arm64

Asyncpreempt on linux/arm64 can sometimes restart a sequence of
instructions which will make breakpoint appear to be hit twice in some
cases.

pkg/proc/native/proc.go

@@ -266,11 +266,23 @@ func (dbp *nativeProcess) initialize(path string, debugInfoDirs []string) (*proc
 		stopReason = proc.StopAttached
 	}
 	tgt, err := proc.NewTarget(dbp, dbp.pid, dbp.memthread, proc.NewTargetConfig{
-		Path:                path,
-		DebugInfoDirs:       debugInfoDirs,
-		DisableAsyncPreempt: runtime.GOOS == "windows" || runtime.GOOS == "freebsd",
-		StopReason:          stopReason,
-		CanDump:             runtime.GOOS == "linux"})
+		Path:          path,
+		DebugInfoDirs: debugInfoDirs,
+
+		// We disable asyncpreempt for the following reasons:
+		//  - on Windows asyncpreempt is incompatible with debuggers, see:
+		//    https://github.com/golang/go/issues/36494
+		//  - freebsd's backend is generally broken and asyncpreempt makes it even more so, see:
+		//    https://github.com/go-delve/delve/issues/1754
+		//  - on linux/arm64 asyncpreempt can sometimes restart a sequence of
+		//    instructions, if the sequence happens to contain a breakpoint it will
+		//    look like the breakpoint was hit twice when it was "logically" only
+		//    executed once.
+		//    See: https://go-review.googlesource.com/c/go/+/208126
+		DisableAsyncPreempt: runtime.GOOS == "windows" || runtime.GOOS == "freebsd" || (runtime.GOOS == "linux" && runtime.GOARCH == "arm64"),
+
+		StopReason: stopReason,
+		CanDump:    runtime.GOOS == "linux"})
 	if err != nil {
 		return nil, err
 	}