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Merged
a-nogikh merged 3 commits into from
Jan 20, 2026
Merged

assorted subsystem updates #6633

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40e6d5f
pkg/subsystem: export debug info
a-nogikh Jan 19, 2026
07454ae
pkg/subsystem: adjust the wildcard matching rules
a-nogikh Jan 19, 2026
700464d
pkg/subsystem: regenerate Linux subsystems
a-nogikh Jan 19, 2026
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1 change: 1 addition & 0 deletions dashboard/app/linux_reporting_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,7 @@ func TestFsSubsystemFlow(t *testing.T) {
// The subsystem should have been taken from the guilty path.
c.expectEQ(reply.Subject, "[syzbot] [nilfs?] WARNING in nilfs_dat_commit_end")
assert.ElementsMatch(t, reply.To, []string{
"slava@dubeyko.com",
"konishi.ryusuke@gmail.com",
"linux-kernel@vger.kernel.org",
"linux-nilfs@vger.kernel.org",
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5 changes: 5 additions & 0 deletions pkg/subsystem/entities.go
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Expand Up @@ -82,3 +82,8 @@ type PathRule struct {
func (pr *PathRule) IsEmpty() bool {
return pr.IncludeRegexp == "" && pr.ExcludeRegexp == ""
}

type DebugInfo struct {
ParentChildComment map[*Subsystem]map[*Subsystem]string
FileLists map[*Subsystem][]string
}
5 changes: 3 additions & 2 deletions pkg/subsystem/linux/maintainers.go
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Expand Up @@ -209,7 +209,6 @@ var (

func wildcardToRegexp(wildcard string, store *strings.Builder) {
store.WriteByte('^')

// We diverge a bit from the standard MAINTAINERS rule semantics.
// path/* corresponds to the files belonging to the `path` folder,
// but, since we also infer the parent-child relationship, it's
Expand All @@ -231,7 +230,9 @@ func wildcardToRegexp(wildcard string, store *strings.Builder) {
if tokenStart < len(wildcard) {
store.WriteString(regexp.QuoteMeta(wildcard[tokenStart:]))
}
// get_maintainers.pl script tolerates the absence of / when the wildcard
// points to a folder. Let's do the same.
if wildcard == "" || wildcard[len(wildcard)-1] != '/' {
store.WriteByte('$')
store.WriteString("(?:" + escapedSeparator + "|$)")
}
}
5 changes: 3 additions & 2 deletions pkg/subsystem/linux/maintainers_test.go
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Expand Up @@ -89,12 +89,13 @@ func TestRecordToPathRule(t *testing.T) {
`with-subfolders/a`,
`with-subfolders/a/b`,
`dir/only-one`,
`dir/only-one/a.c`,
`dir/only-one/a/b.c`,
`also-with-subfolders/a.c`,
`also-with-subfolders/b/a.c`,
},
noMatch: []string{
`dir/only-one/a.c`,
`dir/only-one/a/b.c`,
`dir/only-one-plus-suffix`,
},
},
{
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37 changes: 28 additions & 9 deletions pkg/subsystem/linux/parents.go
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Expand Up @@ -3,42 +3,61 @@

package linux

import "github.com/google/syzkaller/pkg/subsystem"
import (
"fmt"

"github.com/google/syzkaller/pkg/subsystem"
)

// parentTransformations applies all subsystem list transformations that have been implemented.
func parentTransformations(matrix *CoincidenceMatrix,
list []*subsystem.Subsystem) ([]*subsystem.Subsystem, error) {
list []*subsystem.Subsystem) ([]*subsystem.Subsystem, parentInfo, error) {
list = dropSmallSubsystems(matrix, list)
list = dropDuplicateSubsystems(matrix, list)
err := setParents(matrix, list)
info, err := setParents(matrix, list)
if err != nil {
return nil, err
return nil, nil, err
}
return list, info, nil
}

type parentInfo map[*subsystem.Subsystem]map[*subsystem.Subsystem]string

func (pi parentInfo) Save(parent, child *subsystem.Subsystem, info string) {
if pi[parent] == nil {
pi[parent] = map[*subsystem.Subsystem]string{}
}
return list, nil
pi[parent][child] = info
}

// setParents attempts to determine the parent-child relations among the extracted subsystems.
// We assume A is a child of B if:
// 1) B covers more paths than A.
// 2) Most of the paths that relate to A also relate to B.
func setParents(matrix *CoincidenceMatrix, list []*subsystem.Subsystem) error {
func setParents(matrix *CoincidenceMatrix, list []*subsystem.Subsystem) (parentInfo, error) {
// Some subsystems might have already been dropeed.
inInput := map[*subsystem.Subsystem]bool{}
for _, item := range list {
inInput[item] = true
}
matrix.NonEmptyPairs(func(a, b *subsystem.Subsystem, count int) {
info := parentInfo{}
matrix.NonEmptyPairs(func(a, b *subsystem.Subsystem, common int) {
if !inInput[a] || !inInput[b] {
return
}
childFiles := matrix.Count(a)
parentFiles := matrix.Count(b)
// Demand that >= 50% paths are related.
if 2*count/matrix.Count(a) >= 1 && matrix.Count(a) < matrix.Count(b) {
if 2*common/childFiles >= 1 && childFiles < parentFiles {
a.Parents = append(a.Parents, b)
info.Save(b, a,
fmt.Sprintf("Auto-inferred: %d common files among %d/%d.",
common, childFiles, parentFiles))
a.ReachableParents() // make sure we haven't created a loop
}
})
transitiveReduction(list)
return nil
return info, nil
}

// dropSmallSubsystems removes subsystems for which we have found only a few matches in the filesystem tree.
Expand Down
4 changes: 2 additions & 2 deletions pkg/subsystem/linux/parents_test.go
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Expand Up @@ -113,13 +113,13 @@ func TestSetParents(t *testing.T) {
"drivers/android/binder.c": {},
}

matrix, err := BuildCoincidenceMatrix(tree,
matrix, _, err := BuildCoincidenceMatrix(tree,
[]*subsystem.Subsystem{kernel, net, wireless, drivers}, nil)
assert.NoError(t, err)

// Calculate parents.

err = setParents(matrix, []*subsystem.Subsystem{kernel, net, wireless, drivers})
_, err = setParents(matrix, []*subsystem.Subsystem{kernel, net, wireless, drivers})
if err != nil {
t.Fatal(err)
}
Expand Down
34 changes: 27 additions & 7 deletions pkg/subsystem/linux/path_coincidence.go
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Original file line number Diff line number Diff line change
Expand Up @@ -7,22 +7,27 @@ import (
"io/fs"
"regexp"
"runtime"
"sort"
"sync"

"github.com/google/syzkaller/pkg/subsystem"
)

func BuildCoincidenceMatrix(root fs.FS, list []*subsystem.Subsystem,
excludeRe *regexp.Regexp) (*CoincidenceMatrix, error) {
excludeRe *regexp.Regexp) (*CoincidenceMatrix, *matrixDebugInfo, error) {
// Create a matcher.
matcher := subsystem.MakePathMatcher(list)
chPaths, chResult := extractSubsystems(matcher)
// The final consumer goroutine.
cm := MakeCoincidenceMatrix()
ready := make(chan struct{})
debug := &matrixDebugInfo{files: map[*subsystem.Subsystem][]string{}}
go func() {
for items := range chResult {
cm.Record(items...)
for item := range chResult {
cm.Record(item.list...)
for _, entity := range item.list {
debug.files[entity] = append(debug.files[entity], item.path)
}
}
ready <- struct{}{}
}()
Expand All @@ -40,23 +45,38 @@ func BuildCoincidenceMatrix(root fs.FS, list []*subsystem.Subsystem,
})
close(chPaths)
<-ready
return cm, err
for _, list := range debug.files {
sort.Strings(list)
}
return cm, debug, err
}

type matrixDebugInfo struct {
files map[*subsystem.Subsystem][]string
}

var (
includePathRe = regexp.MustCompile(`(?:/|\.(?:c|h|S))$`)
)

func extractSubsystems(matcher *subsystem.PathMatcher) (chan<- string, <-chan []*subsystem.Subsystem) {
type extracted struct {
path string
list []*subsystem.Subsystem
}

func extractSubsystems(matcher *subsystem.PathMatcher) (chan<- string, <-chan extracted) {
procs := runtime.NumCPU()
paths, output := make(chan string, procs), make(chan []*subsystem.Subsystem, procs)
paths, output := make(chan string, procs), make(chan extracted, procs)
var wg sync.WaitGroup
for i := 0; i < procs; i++ {
wg.Add(1)
go func() {
defer wg.Done()
for path := range paths {
output <- matcher.Match(path)
output <- extracted{
path: path,
list: matcher.Match(path),
}
}
}()
}
Expand Down
2 changes: 1 addition & 1 deletion pkg/subsystem/linux/path_coincidence_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@ func TestBuildCoincidenceMatrix(t *testing.T) {
"fs/fat/file.c": {},
"net/socket.c": {},
}
matrix, err := BuildCoincidenceMatrix(fs, []*subsystem.Subsystem{vfs, ntfs, ext4, kernel}, nil)
matrix, _, err := BuildCoincidenceMatrix(fs, []*subsystem.Subsystem{vfs, ntfs, ext4, kernel}, nil)
assert.NoError(t, err)

// Test total counts.
Expand Down
3 changes: 2 additions & 1 deletion pkg/subsystem/linux/rules.go
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Expand Up @@ -39,7 +39,6 @@ var (
// - syz_mount_image$vxfs
// - syz_mount_image$zonefs

"bcachefs": {"syz_mount_image$bcachefs"},
"bfs": {"syz_mount_image$bfs"},
"bluetooth": {"syz_emit_vhci"},
"btrfs": {"syz_mount_image$btrfs"},
Expand Down Expand Up @@ -89,6 +88,8 @@ var (
"tomoyo-dev-en@lists.osdn.me": {},
"tomoyo-users-en@lists.osdn.me": {},
"kernel@collabora.com": {},
// The list is too broad and always intersects with other lists.
"x86@kernel.org": {},
},
extraSubsystems: map[string][]string{
"bfs": {"BFS FILE SYSTEM"},
Expand Down
26 changes: 15 additions & 11 deletions pkg/subsystem/linux/subsystems.go
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Expand Up @@ -13,15 +13,16 @@ import (
"github.com/google/syzkaller/pkg/subsystem"
)

func ListFromRepo(repo string) ([]*subsystem.Subsystem, error) {
func ListFromRepo(repo string) ([]*subsystem.Subsystem, *subsystem.DebugInfo, error) {
return listFromRepoInner(os.DirFS(repo), linuxSubsystemRules)
}

// listFromRepoInner allows for better testing.
func listFromRepoInner(root fs.FS, rules *customRules) ([]*subsystem.Subsystem, error) {
func listFromRepoInner(root fs.FS, rules *customRules) ([]*subsystem.Subsystem,
*subsystem.DebugInfo, error) {
records, err := getMaintainers(root)
if err != nil {
return nil, err
return nil, nil, err
}
removeMatchingPatterns(records, dropPatterns)
ctx := &linuxCtx{
Expand All @@ -31,22 +32,22 @@ func listFromRepoInner(root fs.FS, rules *customRules) ([]*subsystem.Subsystem,
}
extraList, err := ctx.groupByRules()
if err != nil {
return nil, err
return nil, nil, err
}
list := append(ctx.groupByList(), extraList...)
matrix, err := BuildCoincidenceMatrix(root, list, dropPatterns)
matrix, matrixDebug, err := BuildCoincidenceMatrix(root, list, dropPatterns)
if err != nil {
return nil, err
return nil, nil, err
}
list, err = parentTransformations(matrix, list)
list, parentDebug, err := parentTransformations(matrix, list)
if err != nil {
return nil, err
return nil, nil, err
}
if err := setSubsystemNames(list); err != nil {
return nil, fmt.Errorf("failed to set names: %w", err)
return nil, nil, fmt.Errorf("failed to set names: %w", err)
}
if err := ctx.applyExtraRules(list); err != nil {
return nil, fmt.Errorf("failed to apply extra rules: %w", err)
return nil, nil, fmt.Errorf("failed to apply extra rules: %w", err)
}

// Sort subsystems by name to keep output consistent.
Expand All @@ -61,7 +62,10 @@ func listFromRepoInner(root fs.FS, rules *customRules) ([]*subsystem.Subsystem,
return a.ExcludeRegexp < b.ExcludeRegexp
})
}
return list, nil
return list, &subsystem.DebugInfo{
ParentChildComment: parentDebug,
FileLists: matrixDebug.files,
}, nil
}

type linuxCtx struct {
Expand Down
10 changes: 5 additions & 5 deletions pkg/subsystem/linux/subsystems_test.go
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Expand Up @@ -13,7 +13,7 @@ import (
)

func TestGroupLinuxSubsystems(t *testing.T) {
subsystems, err := listFromRepoInner(
subsystems, _, err := listFromRepoInner(
prepareTestLinuxRepo(t, []byte(testMaintainers)),
nil)
if err != nil {
Expand Down Expand Up @@ -57,7 +57,7 @@ func TestGroupLinuxSubsystems(t *testing.T) {
}

func TestCustomCallRules(t *testing.T) {
subsystems, err := listFromRepoInner(
subsystems, _, err := listFromRepoInner(
prepareTestLinuxRepo(t, []byte(testMaintainers)),
testRules,
)
Expand Down Expand Up @@ -103,7 +103,7 @@ func TestLinuxSubsystemPaths(t *testing.T) {
// For the list of subsystems, see TestLinuxSubsystemsList.
// Here we rely on the same ones.
repo := prepareTestLinuxRepo(t, []byte(testMaintainers))
subsystems, err := listFromRepoInner(repo, nil)
subsystems, _, err := listFromRepoInner(repo, nil)
if err != nil {
t.Fatal(err)
}
Expand Down Expand Up @@ -164,7 +164,7 @@ func TestLinuxSubsystemParents(t *testing.T) {
// For the list of subsystems, see TestLinuxSubsystemsList.
// Here we rely on the same ones.
repo := prepareTestLinuxRepo(t, []byte(testMaintainers))
subsystems, err := listFromRepoInner(repo, nil)
subsystems, _, err := listFromRepoInner(repo, nil)
if err != nil {
t.Fatal(err)
}
Expand All @@ -177,7 +177,7 @@ func TestLinuxSubsystemParents(t *testing.T) {
})

// Now check that our custom parent rules work.
subsystems2, err := listFromRepoInner(repo, &customRules{
subsystems2, _, err := listFromRepoInner(repo, &customRules{
addParents: map[string][]string{
// Just for the sake of testing.
"fs": {"mm"},
Expand Down
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