pkg/vcs: fetch linux upstream stable before bisections

4 files changed, 32 insertions, 4 deletions

diff --git a/pkg/bisect/bisect.go b/pkg/bisect/bisect.go
index bc442c16a..0948bc653 100644
--- a/pkg/bisect/bisect.go
+++ b/pkg/bisect/bisect.go
@@ -201,6 +201,11 @@ func runImpl(cfg *Config, repo vcs.Repo, inst instance.Env) (*Result, error) {
 }
 
 func (env *env) bisect() (*Result, error) {
+	err := env.bisecter.PrepareBisect()
+	if err != nil {
+		return nil, err
+	}
+
 	cfg := env.cfg
 	if err := build.Clean(cfg.Manager.TargetOS, cfg.Manager.TargetVMArch,
 		cfg.Manager.Type, cfg.Manager.KernelSrc); err != nil {
diff --git a/pkg/vcs/linux.go b/pkg/vcs/linux.go
index a44729233..d2371ca5c 100644
--- a/pkg/vcs/linux.go
+++ b/pkg/vcs/linux.go
@@ -23,6 +23,7 @@ import (
 
 type linux struct {
 	*git
+	vmType string
 }
 
 var (
@@ -30,12 +31,14 @@ var (
 	_ ConfigMinimizer = new(linux)
 )
 
-func newLinux(dir string, opts []RepoOpt) *linux {
+func newLinux(dir string, opts []RepoOpt, vmType string) *linux {
 	ignoreCC := map[string]bool{
 		"stable@vger.kernel.org": true,
 	}
+
 	return &linux{
-		git: newGit(dir, ignoreCC, opts),
+		git:    newGit(dir, ignoreCC, opts),
+		vmType: vmType,
 	}
 }
 
@@ -248,6 +251,18 @@ func linuxAlterConfigs(cf *kconfig.ConfigFile, tags map[string]bool) {
 	}
 }
 
+func (ctx *linux) PrepareBisect() error {
+	if ctx.vmType != "gvisor" {
+		// Some linux repos we fuzz don't import the upstream release git tags. We need tags
+		// to decide which compiler versions to use. Let's fetch upstream for its tags.
+		err := ctx.git.fetchRemote("https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git")
+		if err != nil {
+			return fmt.Errorf("fetching upstream linux failed: %w", err)
+		}
+	}
+	return nil
+}
+
 func (ctx *linux) Bisect(bad, good string, dt debugtracer.DebugTracer, pred func() (BisectResult,
 	error)) ([]*Commit, error) {
 	commits, err := ctx.git.Bisect(bad, good, dt, pred)
diff --git a/pkg/vcs/testos.go b/pkg/vcs/testos.go
index c9acf1781..baadb1a2a 100644
--- a/pkg/vcs/testos.go
+++ b/pkg/vcs/testos.go
@@ -48,3 +48,7 @@ func (ctx *testos) Minimize(target *targets.Target, original, baseline []byte,
 		return original, nil
 	}
 }
+
+func (ctx *testos) PrepareBisect() error {
+	return nil
+}
diff --git a/pkg/vcs/vcs.go b/pkg/vcs/vcs.go
index 2355cac69..ae7bc8508 100644
--- a/pkg/vcs/vcs.go
+++ b/pkg/vcs/vcs.go
@@ -64,6 +64,10 @@ type Repo interface {
 
 // Bisecter may be optionally implemented by Repo.
 type Bisecter interface {
+	// Can be used for last minute preparations like pulling release tags into the bisected repo, which
+	// is required to determin the compiler version to use on linux. Can be an empty function.
+	PrepareBisect() error
+
 	// Bisect bisects good..bad commit range against the provided predicate (wrapper around git bisect).
 	// The predicate should return an error only if there is no way to proceed
 	// (it will abort the process), if possible it should prefer to return BisectSkip.
@@ -172,10 +176,10 @@ const (
 	OptDontSandbox
 )
 
-func NewRepo(os, vm, dir string, opts ...RepoOpt) (Repo, error) {
+func NewRepo(os, vmType, dir string, opts ...RepoOpt) (Repo, error) {
 	switch os {
 	case targets.Linux:
-		return newLinux(dir, opts), nil
+		return newLinux(dir, opts, vmType), nil
 	case targets.Akaros:
 		return newAkaros(dir, opts), nil
 	case targets.Fuchsia: