pkg/kconfig: store minimization results

Store config options identified using DebugTracer. Also change bisection
and configuration minimization code to use new DebugTracer.

9 files changed, 50 insertions, 58 deletions

diff --git a/pkg/bisect/bisect.go b/pkg/bisect/bisect.go
index 76c518e6c..07f47ccde 100644
--- a/pkg/bisect/bisect.go
+++ b/pkg/bisect/bisect.go
@@ -5,11 +5,10 @@ package bisect
 
 import (
 	"fmt"
-	"io"
-	"path/filepath"
 	"time"
 
 	"github.com/google/syzkaller/pkg/build"
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/pkg/hash"
 	"github.com/google/syzkaller/pkg/instance"
 	"github.com/google/syzkaller/pkg/mgrconfig"
@@ -19,11 +18,10 @@ import (
 )
 
 type Config struct {
-	Trace     io.Writer
+	Trace     debugtracer.DebugTracer
 	Fix       bool
 	BinDir    string
 	Ccache    string
-	DebugDir  string
 	Timeout   time.Duration
 	Kernel    KernelConfig
 	Syzkaller SyzkallerConfig
@@ -540,11 +538,7 @@ func (env *env) processResults(current *vcs.Commit, results []error) (bad, good
 }
 
 func (env *env) saveDebugFile(hash string, idx int, data []byte) {
-	if env.cfg.DebugDir == "" || len(data) == 0 {
-		return
-	}
-	osutil.MkdirAll(env.cfg.DebugDir)
-	osutil.WriteFile(filepath.Join(env.cfg.DebugDir, fmt.Sprintf("%v.%v", hash, idx)), data)
+	env.cfg.Trace.SaveFile(fmt.Sprintf("%v.%v", hash, idx), data)
 }
 
 func checkConfig(cfg *Config) error {
@@ -564,5 +558,5 @@ func checkConfig(cfg *Config) error {
 }
 
 func (env *env) log(msg string, args ...interface{}) {
-	fmt.Fprintf(env.cfg.Trace, msg+"\n", args...)
+	env.cfg.Trace.Log(msg, args...)
 }
diff --git a/pkg/bisect/bisect_test.go b/pkg/bisect/bisect_test.go
index db4409a5c..e71903c98 100644
--- a/pkg/bisect/bisect_test.go
+++ b/pkg/bisect/bisect_test.go
@@ -4,13 +4,13 @@
 package bisect
 
 import (
-	"bytes"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"strconv"
 	"testing"
 
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/pkg/hash"
 	"github.com/google/syzkaller/pkg/instance"
 	"github.com/google/syzkaller/pkg/mgrconfig"
@@ -122,10 +122,9 @@ func runBisection(t *testing.T, baseDir string, test BisectionTest) (*Result, er
 	if err != nil {
 		t.Fatal(err)
 	}
-	trace := new(bytes.Buffer)
 	cfg := &Config{
 		Fix:   test.fix,
-		Trace: trace,
+		Trace: &debugtracer.TestTracer{T: t},
 		Manager: &mgrconfig.Config{
 			Derived: mgrconfig.Derived{
 				TargetOS:     targets.TestOS,
@@ -147,7 +146,6 @@ func runBisection(t *testing.T, baseDir string, test BisectionTest) (*Result, er
 		test: test,
 	}
 	res, err := runImpl(cfg, r, inst)
-	t.Log(trace.String())
 	return res, err
 }
 
diff --git a/pkg/kconfig/minimize.go b/pkg/kconfig/minimize.go
index bbcb95414..bbc66c4c1 100644
--- a/pkg/kconfig/minimize.go
+++ b/pkg/kconfig/minimize.go
@@ -4,9 +4,10 @@
 package kconfig
 
 import (
-	"fmt"
-	"io"
 	"sort"
+
+	"github.com/google/syzkaller/pkg/debugtracer"
+	"github.com/google/syzkaller/pkg/osutil"
 )
 
 // Minimize finds an equivalent with respect to the provided predicate, but smaller config.
@@ -15,15 +16,14 @@ import (
 // mostly by adding more configs. The minimization procedure thus consists of figuring out what set of configs that
 // are present in full and are not present in base affect the predicate.
 func (kconf *KConfig) Minimize(base, full *ConfigFile, pred func(*ConfigFile) (bool, error),
-	tw io.Writer) (*ConfigFile, error) {
-	trace := traceLogger{tw}
+	dt debugtracer.DebugTracer) (*ConfigFile, error) {
 	diff, other := kconf.missingConfigs(base, full)
-	trace.log("kconfig minimization: base=%v full=%v diff=%v", len(base.Configs), len(full.Configs), len(diff))
+	dt.Log("kconfig minimization: base=%v full=%v diff=%v", len(base.Configs), len(full.Configs), len(diff))
 	// First, check the base config as is, it is the smallest we can possibly get.
 	if res, err := pred(base); err != nil {
 		return nil, err
 	} else if res {
-		trace.log("base config crashes")
+		dt.Log("base config crashes")
 		return base, nil
 	}
 	// Since base does not crash, full config is our best bet for now.
@@ -45,7 +45,7 @@ top:
 	for len(diff) >= 2 {
 		half := len(diff) / 2
 		for _, part := range [][]string{diff[:half], diff[half:]} {
-			trace.log("trying half: %v", part)
+			dt.Log("trying half: %v", part)
 			closure := kconf.addDependencies(base, full, part)
 			candidate := base.clone()
 			// Always move all non-tristate configs from full to base as we don't minimize them.
@@ -60,20 +60,21 @@ top:
 				return nil, err
 			}
 			if res {
-				trace.log("half crashed")
+				dt.Log("half crashed")
 				diff = part
 				current = candidate
 				suspects = closure
 				continue top
 			}
 		}
-		trace.log("both halves did not crash")
+		dt.Log("both halves did not crash")
 		break
 	}
 	if suspects != nil {
-		trace.log("resulting configs: %v", suspects)
+		dt.Log("resulting configs: %v", suspects)
+		kconf.writeSuspects(dt, suspects)
 	} else {
-		trace.log("only full config crashes")
+		dt.Log("only full config crashes")
 	}
 	return current, nil
 }
@@ -110,10 +111,15 @@ func (kconf *KConfig) addDependencies(base, full *ConfigFile, configs []string)
 	return sorted
 }
 
-type traceLogger struct{ io.Writer }
+const CauseConfigFile = "cause.config"
+
+func (kconf *KConfig) writeSuspects(dt debugtracer.DebugTracer, suspects []string) {
+	cf := &ConfigFile{
+		Map: make(map[string]*Config),
+	}
 
-func (trace traceLogger) log(msg string, args ...interface{}) {
-	if trace.Writer != nil {
-		fmt.Fprintf(trace.Writer, msg+"\n", args...)
+	for _, cfg := range suspects {
+		cf.Set(cfg, Yes)
 	}
+	osutil.WriteFile(CauseConfigFile, cf.Serialize())
 }
diff --git a/pkg/kconfig/minimize_test.go b/pkg/kconfig/minimize_test.go
index 28dca33bd..1e1d2b0f2 100644
--- a/pkg/kconfig/minimize_test.go
+++ b/pkg/kconfig/minimize_test.go
@@ -4,10 +4,10 @@
 package kconfig
 
 import (
-	"bytes"
 	"fmt"
 	"testing"
 
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/sys/targets"
 )
 
@@ -106,9 +106,7 @@ CONFIG_ROSE=y
 	}
 	for i, test := range tests {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
-			trace := new(bytes.Buffer)
-			res, err := kconf.Minimize(base, full, test.pred, trace)
-			t.Log(trace.String())
+			res, err := kconf.Minimize(base, full, test.pred, &debugtracer.TestTracer{T: t})
 			if err != nil {
 				t.Fatal(err)
 			}
diff --git a/pkg/vcs/git.go b/pkg/vcs/git.go
index 1a90341ac..163f3e497 100644
--- a/pkg/vcs/git.go
+++ b/pkg/vcs/git.go
@@ -7,7 +7,6 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"io"
 	"net/mail"
 	"os"
 	"os/exec"
@@ -16,6 +15,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/pkg/hash"
 	"github.com/google/syzkaller/pkg/log"
 	"github.com/google/syzkaller/pkg/osutil"
@@ -431,7 +431,8 @@ func splitEmail(email string) (user, domain string, err error) {
 	return
 }
 
-func (git *git) Bisect(bad, good string, trace io.Writer, pred func() (BisectResult, error)) ([]*Commit, error) {
+func (git *git) Bisect(bad, good string, dt debugtracer.DebugTracer, pred func() (BisectResult,
+	error)) ([]*Commit, error) {
 	git.reset()
 	firstBad, err := git.getCommit(bad)
 	if err != nil {
@@ -442,7 +443,7 @@ func (git *git) Bisect(bad, good string, trace io.Writer, pred func() (BisectRes
 		return nil, err
 	}
 	defer git.reset()
-	fmt.Fprintf(trace, "# git bisect start %v %v\n%s", bad, good, output)
+	dt.Log("# git bisect start %v %v\n%s", bad, good, output)
 	current, err := git.HeadCommit()
 	if err != nil {
 		return nil, err
@@ -463,7 +464,7 @@ func (git *git) Bisect(bad, good string, trace io.Writer, pred func() (BisectRes
 			firstBad = current
 		}
 		output, err = git.git("bisect", bisectTerms[res])
-		fmt.Fprintf(trace, "# git bisect %v %v\n%s", bisectTerms[res], current.Hash, output)
+		dt.Log("# git bisect %v %v\n%s", bisectTerms[res], current.Hash, output)
 		if err != nil {
 			if bytes.Contains(output, []byte("There are only 'skip'ped commits left to test")) {
 				return git.bisectInconclusive(output)
diff --git a/pkg/vcs/git_repo_test.go b/pkg/vcs/git_repo_test.go
index a2610315f..9a044e870 100644
--- a/pkg/vcs/git_repo_test.go
+++ b/pkg/vcs/git_repo_test.go
@@ -12,6 +12,7 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/syzkaller/pkg/debugtracer"
 )
 
 func init() {
@@ -378,7 +379,7 @@ func TestBisect(t *testing.T) {
 	}
 	for i, test := range tests {
 		t.Logf("TEST %v", i)
-		result, err := repo.repo.Bisect(commits[4], commits[0], (*testWriter)(t), test.pred)
+		result, err := repo.repo.Bisect(commits[4], commits[0], &debugtracer.TestTracer{T: t}, test.pred)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -394,10 +395,3 @@ func TestBisect(t *testing.T) {
 		}
 	}
 }
-
-type testWriter testing.T
-
-func (t *testWriter) Write(data []byte) (int, error) {
-	(*testing.T)(t).Log(string(data))
-	return len(data), nil
-}
diff --git a/pkg/vcs/linux.go b/pkg/vcs/linux.go
index a99215528..93c9ca045 100644
--- a/pkg/vcs/linux.go
+++ b/pkg/vcs/linux.go
@@ -6,7 +6,6 @@ package vcs
 import (
 	"bytes"
 	"fmt"
-	"io"
 	"net/mail"
 	"path/filepath"
 	"regexp"
@@ -15,6 +14,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/pkg/kconfig"
 	"github.com/google/syzkaller/pkg/osutil"
 	"github.com/google/syzkaller/prog"
@@ -237,8 +237,9 @@ func linuxAlterConfigs(cf *kconfig.ConfigFile, tags map[string]bool) {
 	}
 }
 
-func (ctx *linux) Bisect(bad, good string, trace io.Writer, pred func() (BisectResult, error)) ([]*Commit, error) {
-	commits, err := ctx.git.Bisect(bad, good, trace, pred)
+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)
 	if len(commits) == 1 {
 		ctx.addMaintainers(commits[0])
 	}
@@ -309,10 +310,10 @@ func ParseMaintainersLinux(text []byte) Recipients {
 
 const configBisectTag = "# Minimized by syzkaller"
 
-func (ctx *linux) Minimize(target *targets.Target, original, baseline []byte, trace io.Writer,
-	pred func(test []byte) (BisectResult, error)) ([]byte, error) {
+func (ctx *linux) Minimize(target *targets.Target, original, baseline []byte,
+	dt debugtracer.DebugTracer, pred func(test []byte) (BisectResult, error)) ([]byte, error) {
 	if bytes.HasPrefix(original, []byte(configBisectTag)) {
-		fmt.Fprintf(trace, "# configuration already minimized\n")
+		dt.Log("# configuration already minimized\n")
 		return original, nil
 	}
 	kconf, err := kconfig.Parse(target, filepath.Join(ctx.git.dir, "Kconfig"))
@@ -333,7 +334,7 @@ func (ctx *linux) Minimize(target *targets.Target, original, baseline []byte, tr
 		res, err := pred(serialize(candidate))
 		return res == BisectBad, err
 	}
-	minConfig, err := kconf.Minimize(baselineConfig, originalConfig, kconfPred, trace)
+	minConfig, err := kconf.Minimize(baselineConfig, originalConfig, kconfPred, dt)
 	if err != nil {
 		return nil, err
 	}
diff --git a/pkg/vcs/testos.go b/pkg/vcs/testos.go
index fa9f7cc9b..c9acf1781 100644
--- a/pkg/vcs/testos.go
+++ b/pkg/vcs/testos.go
@@ -5,8 +5,8 @@ package vcs
 
 import (
 	"fmt"
-	"io"
 
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/sys/targets"
 )
 
@@ -30,8 +30,8 @@ func (ctx *testos) EnvForCommit(binDir, commit string, kernelConfig []byte) (*Bi
 	return &BisectEnv{KernelConfig: kernelConfig}, nil
 }
 
-func (ctx *testos) Minimize(target *targets.Target, original, baseline []byte, trace io.Writer,
-	pred func(test []byte) (BisectResult, error)) ([]byte, error) {
+func (ctx *testos) Minimize(target *targets.Target, original, baseline []byte,
+	dt debugtracer.DebugTracer, pred func(test []byte) (BisectResult, error)) ([]byte, error) {
 	if res, err := pred(baseline); err != nil {
 		return nil, err
 	} else if res == BisectBad {
diff --git a/pkg/vcs/vcs.go b/pkg/vcs/vcs.go
index acdb9837e..7ede983f6 100644
--- a/pkg/vcs/vcs.go
+++ b/pkg/vcs/vcs.go
@@ -7,7 +7,6 @@ package vcs
 import (
 	"bytes"
 	"fmt"
-	"io"
 	"net/mail"
 	"regexp"
 	"sort"
@@ -15,6 +14,7 @@ import (
 	"time"
 
 	"github.com/google/syzkaller/dashboard/dashapi"
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/pkg/osutil"
 	"github.com/google/syzkaller/sys/targets"
 )
@@ -116,7 +116,7 @@ type Bisecter interface {
 	// Progress of the process is streamed to the provided trace.
 	// Returns the first commit on which the predicate returns BisectBad,
 	// or multiple commits if bisection is inconclusive due to BisectSkip.
-	Bisect(bad, good string, trace io.Writer, pred func() (BisectResult, error)) ([]*Commit, error)
+	Bisect(bad, good string, dt debugtracer.DebugTracer, pred func() (BisectResult, error)) ([]*Commit, error)
 
 	// PreviousReleaseTags returns list of preceding release tags that are reachable from the given commit.
 	// If the commit itself has a release tag, this tag is not included.
@@ -128,7 +128,7 @@ type Bisecter interface {
 }
 
 type ConfigMinimizer interface {
-	Minimize(target *targets.Target, original, baseline []byte, trace io.Writer,
+	Minimize(target *targets.Target, original, baseline []byte, dt debugtracer.DebugTracer,
 		pred func(test []byte) (BisectResult, error)) ([]byte, error)
 }