pkg/subsystem: extract filesystems from guilty path

As we can easily do the subsystem <-> path mapping, let's also use it
for determining the actual involved filesystem.

4 files changed, 50 insertions, 28 deletions

diff --git a/dashboard/app/app_test.go b/dashboard/app/app_test.go
index 3fa2e8499..400f16050 100644
--- a/dashboard/app/app_test.go
+++ b/dashboard/app/app_test.go
@@ -357,7 +357,7 @@ var testConfig = &GlobalConfig{
 					},
 				},
 			},
-			Subsystems: &SubsystemsConfig{
+			Subsystems: SubsystemsConfig{
 				SubsystemCc: subsystem.LinuxGetMaintainers,
 			},
 		},
diff --git a/dashboard/app/config_linux_test.go b/dashboard/app/config_linux_test.go
index 595f4b47a..1d4e82ac2 100644
--- a/dashboard/app/config_linux_test.go
+++ b/dashboard/app/config_linux_test.go
@@ -46,8 +46,15 @@ func TestFsSubsystemFlow(t *testing.T) {
 	client.ReportCrash(crash)
 
 	reply = c.pollEmailBug()
-	// We have no means to determine the subsystem now, so it shouldn't be anywhere.
-	c.expectEQ(reply.Subject, "[syzbot] WARNING in nilfs_dat_commit_end")
+	// The subsystem should have been taken from the guilty path.
+	c.expectEQ(reply.Subject, "[syzbot] [nilfs2?] WARNING in nilfs_dat_commit_end")
+	c.expectEQ(reply.To, []string{
+		"konishi.ryusuke@gmail.com",
+		"linux-kernel@vger.kernel.org",
+		"linux-nilfs@vger.kernel.org",
+		"maintainer@kernel.org",
+		"test@syzkaller.com",
+	})
 
 	// C. Send a possibly vfs bug without a reproducer.
 	// -----------------------------------------
diff --git a/pkg/subsystem/extract.go b/pkg/subsystem/extract.go
index 4d952011f..1908f5e54 100644
--- a/pkg/subsystem/extract.go
+++ b/pkg/subsystem/extract.go
@@ -5,6 +5,7 @@ package subsystem
 
 import (
 	"regexp"
+	"sync"
 
 	"github.com/google/syzkaller/prog"
 )
@@ -58,9 +59,24 @@ func linuxPathToSubsystems(path string) []string {
 	if vfsPathRegexp.MatchString(path) {
 		ret = append(ret, "vfs")
 	}
+	linuxSubsystemsOnce.Do(func() {
+		for name, info := range linuxSubsystems {
+			linuxSubsystemRegexps[name] = regexp.MustCompile("^/?" + info.path + ".*")
+		}
+	})
+	for name, pattern := range linuxSubsystemRegexps {
+		if pattern.MatchString(path) {
+			ret = append(ret, name)
+		}
+	}
 	return ret
 }
 
+var (
+	linuxSubsystemsOnce   sync.Once
+	linuxSubsystemRegexps = map[string]*regexp.Regexp{}
+)
+
 func linuxCallToSubsystems(call string) []string {
 	name := linuxCallToSubsystemsMap[call]
 	if name != "" {
diff --git a/pkg/subsystem/extract_test.go b/pkg/subsystem/extract_test.go
index 862d1a6e5..eb04ff6ce 100644
--- a/pkg/subsystem/extract_test.go
+++ b/pkg/subsystem/extract_test.go
@@ -4,7 +4,6 @@
 package subsystem
 
 import (
-	"reflect"
 	"sort"
 	"testing"
 
@@ -12,27 +11,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestSimpleLinuxExtract(t *testing.T) {
-	se := MakeLinuxSubsystemExtractor()
-
-	ret := se.Extract(&Crash{
-		OS: targets.Linux,
-		GuiltyFiles: []string{
-			"fs/ext4/abc.c",
-		},
-	})
-	assert.Empty(t, ret, "the test should have found 0 subsystems")
-
-	ret = se.Extract(&Crash{
-		OS: targets.Linux,
-		GuiltyFiles: []string{
-			"fs/ext4/abc.c",
-			"fs/def.c",
-		},
-	})
-	assert.Exactly(t, ret, []string{"vfs"}, "the test should have only found vfs")
-}
-
 func TestProgCallRules(t *testing.T) {
 	se := &SubsystemExtractor{
 		pathToSubsystems: linuxPathToSubsystems,
@@ -78,6 +56,10 @@ func TestFsSubsystemExtraction(t *testing.T) {
 		subsystems []string
 	}{
 		{
+			guilty:     "fs/abc.c",
+			subsystems: []string{"vfs"},
+		},
+		{
 			guilty: "fs/nilfs2/dat.c",
 			// nolint: lll
 			prog: `syz_mount_image$nilfs2(&(0x7f0000000000), &(0x7f0000000100)='./file0\x00', 0x100000, 0x3b, &(0x7f0000000200)=[{&(0x7f0000011240)="02", 0x1}, {&(0x7f0000012a40)="03000000", 0x4, 0x1}], 0x0, &(0x7f00000131c0), 0x1)
@@ -94,6 +76,24 @@ mkdirat(r0, &(0x7f0000000280)='./bus/file0\x00', 0x0)
 renameat2(r0, &(0x7f00000004c0)='./file0\x00', r0, &(0x7f0000000500)='./bus/file0/file0\x00', 0x0)`,
 			subsystems: []string{"ntfs3", "vfs"},
 		},
+		{
+			guilty: "fs/ext4/file.c",
+			// nolint: lll
+			prog: `syz_mount_image$ntfs3(&(0x7f0000000240), &(0x7f000001f3c0)='./file0\x00', 0xc40, &(0x7f00000005c0)=ANY=[@ANYBLOB="0032"], 0x3, 0x1f398, &(0x7f000003e7c0)="111")
+r0 = openat(0xffffffffffffff9c, &(0x7f0000000040)='.\x00', 0x0, 0x0)
+mkdirat(r0, &(0x7f0000000180)='./bus\x00', 0x0)
+mkdirat(r0, &(0x7f0000000280)='./bus/file0\x00', 0x0)
+renameat2(r0, &(0x7f00000004c0)='./file0\x00', r0, &(0x7f0000000500)='./bus/file0/file0\x00', 0x0)`,
+			subsystems: []string{"ntfs3", "ext4"},
+		},
+		{
+			guilty:     "fs/gfs2/ops_fstype.c",
+			subsystems: []string{"gfs2"},
+		},
+		{
+			guilty:     "net/mac80211/main.c",
+			subsystems: []string{},
+		},
 	}
 
 	for i, test := range tests {
@@ -103,8 +103,7 @@ renameat2(r0, &(0x7f00000004c0)='./file0\x00', r0, &(0x7f0000000500)='./bus/file
 			SyzRepro:    test.prog,
 		})
 		sort.Strings(ret)
-		if !reflect.DeepEqual(ret, test.subsystems) {
-			t.Fatalf("test #%d: got %+v, wanted %+v", i, ret, test.subsystems)
-		}
+		sort.Strings(test.subsystems)
+		assert.Exactlyf(t, ret, test.subsystems, "#%d: invalid resulting subsystems", i)
 	}
 }