sys/syz-extract: fix a deadlock

The jobs channel needs to have capacity to hold all files from all arches
since they may all be queued to the channel at the same time.
The bug was introduced in 44a5ca633e
("pkg/ast, pkg/compiler: support per-file metadata").
Restore full channel capacity.

Fixes #3197

1 files changed, 10 insertions, 8 deletions

diff --git a/sys/syz-extract/extract.go b/sys/syz-extract/extract.go
index 117c10e58..c3629ee17 100644
--- a/sys/syz-extract/extract.go
+++ b/sys/syz-extract/extract.go
@@ -80,7 +80,7 @@ func main() {
 	if extractor == nil {
 		tool.Failf("unknown os: %v", OS)
 	}
-	arches, err := createArches(OS, archList(OS, *flagArch), flag.Args())
+	arches, nfiles, err := createArches(OS, archList(OS, *flagArch), flag.Args())
 	if err != nil {
 		tool.Fail(err)
 	}
@@ -92,7 +92,7 @@ func main() {
 		tool.Fail(err)
 	}
 
-	jobC := make(chan interface{}, len(arches))
+	jobC := make(chan interface{}, len(arches)+nfiles)
 	for _, arch := range arches {
 		jobC <- arch
 	}
@@ -169,26 +169,27 @@ func worker(extractor Extractor, jobC chan interface{}) {
 	}
 }
 
-func createArches(OS string, archArray, files []string) ([]*Arch, error) {
+func createArches(OS string, archArray, files []string) ([]*Arch, int, error) {
 	errBuf := new(bytes.Buffer)
 	eh := func(pos ast.Pos, msg string) {
 		fmt.Fprintf(errBuf, "%v: %v\n", pos, msg)
 	}
 	top := ast.ParseGlob(filepath.Join("sys", OS, "*.txt"), eh)
 	if top == nil {
-		return nil, fmt.Errorf("%v", errBuf.String())
+		return nil, 0, fmt.Errorf("%v", errBuf.String())
 	}
 	allFiles := compiler.FileList(top, OS, eh)
 	if allFiles == nil {
-		return nil, fmt.Errorf("%v", errBuf.String())
+		return nil, 0, fmt.Errorf("%v", errBuf.String())
 	}
+	nfiles := 0
 	var arches []*Arch
 	for _, archStr := range archArray {
 		buildDir := ""
 		if *flagBuild {
 			dir, err := ioutil.TempDir("", "syzkaller-kernel-build")
 			if err != nil {
-				return nil, fmt.Errorf("failed to create temp dir: %v", err)
+				return nil, 0, fmt.Errorf("failed to create temp dir: %v", err)
 			}
 			buildDir = dir
 		} else if *flagBuildDir != "" {
@@ -199,7 +200,7 @@ func createArches(OS string, archArray, files []string) ([]*Arch, error) {
 
 		target := targets.Get(OS, archStr)
 		if target == nil {
-			return nil, fmt.Errorf("unknown arch: %v", archStr)
+			return nil, 0, fmt.Errorf("unknown arch: %v", archStr)
 		}
 
 		arch := &Arch{
@@ -228,8 +229,9 @@ func createArches(OS string, archArray, files []string) ([]*Arch, error) {
 			})
 		}
 		arches = append(arches, arch)
+		nfiles += len(arch.files)
 	}
-	return arches, nil
+	return arches, nfiles, nil
 }
 
 func archList(OS, arches string) []string {