Split ioworkload scenarios.go into per-category files

Split the 2494-line scenarios.go monolith into 14 focused files by
syscall category: open, readwrite, close, dup, fcntl, rename, link,
unlink, dir, stat, sync, truncate, iouring, plus the slimmed-down
scenarios.go containing only the registry map, makeTempDir, and crash.

Extracted rawLink, rawSymlink, rawReadlink helpers in scenario_link.go
to reduce code duplication in linkBasic.

Task: #349 (Go best practices: split oversized scenarios file)
Amp-Thread-ID: https://ampcode.com/threads/T-019c81c6-e1b6-747a-9144-40f6be997e60
Co-authored-by: Amp <amp@ampcode.com>

1 files changed, 0 insertions, 2386 deletions

diff --git a/integrationtests/cmd/ioworkload/scenarios.go b/integrationtests/cmd/ioworkload/scenarios.go
index 0344999..0103c6d 100644
--- a/integrationtests/cmd/ioworkload/scenarios.go
+++ b/integrationtests/cmd/ioworkload/scenarios.go
@@ -3,11 +3,6 @@ package main
 import (
 	"fmt"
 	"os"
-	"os/exec"
-	"path/filepath"
-	"runtime"
-	"syscall"
-	"unsafe"
 )
 
 // scenarios maps scenario names to their execution functions.
@@ -106,2387 +101,6 @@ func makeTempDir(prefix string) (string, func(), error) {
 	return dir, cleanup, nil
 }
 
-// openBasic opens a file with O_RDWR|O_CREAT, then closes it.
-func openBasic() error {
-	dir, cleanup, err := makeTempDir("open-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "testfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	return syscall.Close(fd)
-}
-
-// openCreat creates a file via raw SYS_CREAT.
-// Go's syscall.Creat wraps Open which delegates to openat on amd64,
-// so we use the raw syscall to actually exercise the creat tracepoint.
-func openCreat() error {
-	dir, cleanup, err := makeTempDir("open-creat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "creatfile.txt")
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	fd, _, errno := syscall.Syscall(syscall.SYS_CREAT, uintptr(unsafe.Pointer(pathBytes)), 0o644, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno != 0 {
-		return fmt.Errorf("creat: %w", errno)
-	}
-	return syscall.Close(int(fd))
-}
-
-// openEnoent attempts to open a nonexistent file path. The openat syscall
-// returns ENOENT, but ior should still capture the enter_openat tracepoint
-// because the filename is read on entry before the syscall executes.
-func openEnoent() error {
-	dir, cleanup, err := makeTempDir("open-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "nonexistent", "enoentfile.txt")
-	_, err = syscall.Open(path, syscall.O_RDONLY, 0)
-	if err == nil {
-		return fmt.Errorf("expected ENOENT, but open succeeded")
-	}
-	return nil
-}
-
-// openRdonlyWrite opens a file O_RDONLY, then attempts to write to it.
-// The write fails with EBADF, but ior should capture both the openat
-// tracepoint and the write tracepoint.
-func openRdonlyWrite() error {
-	dir, cleanup, err := makeTempDir("open-rdonly-write")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "rdonlyfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("create file: %w", err)
-	}
-	syscall.Close(fd)
-
-	fd, err = syscall.Open(path, syscall.O_RDONLY, 0)
-	if err != nil {
-		return fmt.Errorf("open rdonly: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	_, err = syscall.Write(fd, []byte("should fail"))
-	if err == nil {
-		return fmt.Errorf("expected write to rdonly fd to fail")
-	}
-	return nil
-}
-
-// openPidFilter spawns a child process that performs file I/O. Since ior
-// filters by the workload PID, the child's I/O should NOT appear in results.
-// The parent also performs its own open so the test can verify positive and
-// negative expectations simultaneously.
-func openPidFilter() error {
-	dir, cleanup, err := makeTempDir("open-pid-filter")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	// Parent opens a file (should be captured by ior).
-	parentPath := filepath.Join(dir, "parentfile.txt")
-	fd, err := syscall.Open(parentPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("parent open: %w", err)
-	}
-	syscall.Close(fd)
-
-	// Spawn a child process that creates a file with a distinctive name.
-	childPath := filepath.Join(dir, "childfile.txt")
-	cmd := exec.Command("touch", childPath)
-	if err := cmd.Run(); err != nil {
-		return fmt.Errorf("child touch: %w", err)
-	}
-	return nil
-}
-
-// readwriteBasic opens a file, writes data, seeks to start, reads it back.
-func readwriteBasic() error {
-	dir, cleanup, err := makeTempDir("readwrite-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "rwfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	data := []byte("hello from ioworkload")
-	if _, err := syscall.Write(fd, data); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	if _, err := syscall.Seek(fd, 0, 0); err != nil {
-		return fmt.Errorf("seek: %w", err)
-	}
-
-	buf := make([]byte, len(data))
-	if _, err := syscall.Read(fd, buf); err != nil {
-		return fmt.Errorf("read: %w", err)
-	}
-	return nil
-}
-
-// readwritePread opens a file, writes data, then reads it back via pread64.
-func readwritePread() error {
-	dir, cleanup, err := makeTempDir("readwrite-pread")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "preadfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	data := []byte("pread test data")
-	if _, err := syscall.Write(fd, data); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-
-	buf := make([]byte, len(data))
-	if _, err := syscall.Pread(fd, buf, 0); err != nil {
-		return fmt.Errorf("pread: %w", err)
-	}
-	return nil
-}
-
-// readwritePwrite opens a file and writes data via pwrite64.
-func readwritePwrite() error {
-	dir, cleanup, err := makeTempDir("readwrite-pwrite")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "pwritefile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	if _, err := syscall.Pwrite(fd, []byte("pwrite test data"), 0); err != nil {
-		return fmt.Errorf("pwrite: %w", err)
-	}
-	return nil
-}
-
-// readwriteReadv opens a file, writes data, then reads it back via readv.
-func readwriteReadv() error {
-	dir, cleanup, err := makeTempDir("readwrite-readv")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "readvfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	data := []byte("readv test data here")
-	if _, err := syscall.Write(fd, data); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	if _, err := syscall.Seek(fd, 0, 0); err != nil {
-		return fmt.Errorf("seek: %w", err)
-	}
-
-	buf1 := make([]byte, 5)
-	buf2 := make([]byte, 15)
-	iovs := []syscall.Iovec{
-		{Base: &buf1[0], Len: uint64(len(buf1))},
-		{Base: &buf2[0], Len: uint64(len(buf2))},
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_READV, uintptr(fd), uintptr(unsafe.Pointer(&iovs[0])), uintptr(len(iovs)))
-	runtime.KeepAlive(buf1)
-	runtime.KeepAlive(buf2)
-	if errno != 0 {
-		return fmt.Errorf("readv: %w", errno)
-	}
-	return nil
-}
-
-// readwriteWritev opens a file and writes data via writev.
-func readwriteWritev() error {
-	dir, cleanup, err := makeTempDir("readwrite-writev")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "writevfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	buf1 := []byte("writev ")
-	buf2 := []byte("test data")
-	iovs := []syscall.Iovec{
-		{Base: &buf1[0], Len: uint64(len(buf1))},
-		{Base: &buf2[0], Len: uint64(len(buf2))},
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_WRITEV, uintptr(fd), uintptr(unsafe.Pointer(&iovs[0])), uintptr(len(iovs)))
-	runtime.KeepAlive(buf1)
-	runtime.KeepAlive(buf2)
-	if errno != 0 {
-		return fmt.Errorf("writev: %w", errno)
-	}
-	return nil
-}
-
-// readwriteWronlyRead opens a file O_WRONLY, then attempts to read from it.
-// The read fails with EBADF, but ior should capture the enter_read tracepoint
-// because arguments are read on syscall entry before the kernel returns an error.
-func readwriteWronlyRead() error {
-	dir, cleanup, err := makeTempDir("readwrite-wronly-read")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "wronlyfile.txt")
-	fd, err := syscall.Open(path, syscall.O_WRONLY|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	buf := make([]byte, 16)
-	_, err = syscall.Read(fd, buf)
-	if err == nil {
-		return fmt.Errorf("expected read from wronly fd to fail")
-	}
-	return nil
-}
-
-// readwriteRdonlyWrite opens a file O_RDONLY, then attempts to write to it.
-// The write fails with EBADF, but ior should capture the enter_write tracepoint
-// because arguments are read on syscall entry before the kernel returns an error.
-func readwriteRdonlyWrite() error {
-	dir, cleanup, err := makeTempDir("readwrite-rdonly-write")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "rdonlywritefile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("create file: %w", err)
-	}
-	syscall.Close(fd)
-
-	fd, err = syscall.Open(path, syscall.O_RDONLY, 0)
-	if err != nil {
-		return fmt.Errorf("open rdonly: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	_, err = syscall.Write(fd, []byte("should fail"))
-	if err == nil {
-		return fmt.Errorf("expected write to rdonly fd to fail")
-	}
-	return nil
-}
-
-// readwritePreadInvalid calls pread64 with a negative offset (-1).
-// The syscall fails with EINVAL, but ior should capture the enter_pread64
-// tracepoint because arguments are read on syscall entry.
-func readwritePreadInvalid() error {
-	dir, cleanup, err := makeTempDir("readwrite-pread-invalid")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "preadinvalid.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	if _, err := syscall.Write(fd, []byte("some data")); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-
-	buf := make([]byte, 16)
-	_, err = syscall.Pread(fd, buf, -1)
-	if err == nil {
-		return fmt.Errorf("expected pread with negative offset to fail")
-	}
-	return nil
-}
-
-// readwritePwriteInvalid calls pwrite64 with a negative offset (-1).
-// The syscall fails with EINVAL, but ior should capture the enter_pwrite64
-// tracepoint because arguments are read on syscall entry.
-func readwritePwriteInvalid() error {
-	dir, cleanup, err := makeTempDir("readwrite-pwrite-invalid")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "pwriteinvalid.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	_, err = syscall.Pwrite(fd, []byte("should fail"), -1)
-	if err == nil {
-		return fmt.Errorf("expected pwrite with negative offset to fail")
-	}
-	return nil
-}
-
-// closeBasic opens multiple files and closes them.
-func closeBasic() error {
-	dir, cleanup, err := makeTempDir("close-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	var fds []int
-	for i := range 3 {
-		path := filepath.Join(dir, fmt.Sprintf("closefile-%d.txt", i))
-		fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-		if err != nil {
-			return fmt.Errorf("open %d: %w", i, err)
-		}
-		fds = append(fds, fd)
-	}
-	for _, fd := range fds {
-		if err := syscall.Close(fd); err != nil {
-			return fmt.Errorf("close fd %d: %w", fd, err)
-		}
-	}
-	return nil
-}
-
-// closeRange opens multiple files and closes a range of them via close_range(2).
-func closeRange() error {
-	dir, cleanup, err := makeTempDir("close-range")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	var fds []int
-	for i := range 3 {
-		path := filepath.Join(dir, fmt.Sprintf("closerangefile-%d.txt", i))
-		fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-		if err != nil {
-			return fmt.Errorf("open %d: %w", i, err)
-		}
-		fds = append(fds, fd)
-	}
-
-	if fds[2]-fds[0] != 2 {
-		return fmt.Errorf("fds not contiguous: %v", fds)
-	}
-
-	first := uintptr(fds[0])
-	last := uintptr(fds[len(fds)-1])
-	_, _, errno := syscall.Syscall(sysCloseRange, first, last, 0)
-	if errno != 0 {
-		return fmt.Errorf("close_range: %w", errno)
-	}
-	return nil
-}
-
-const sysCloseRange = 436
-
-// closeInvalidFd attempts to close a very high fd number that is not open.
-// The close fails with EBADF, but ior should capture the enter_close tracepoint
-// because arguments are read on syscall entry before the kernel returns an error.
-func closeInvalidFd() error {
-	err := syscall.Close(99999)
-	if err == nil {
-		return fmt.Errorf("expected close of invalid fd to fail")
-	}
-	return nil
-}
-
-// closeDoubleClose opens a file, closes it normally, then closes the same fd again.
-// The second close fails with EBADF, but ior should capture both enter_close
-// tracepoints because arguments are read on syscall entry.
-func closeDoubleClose() error {
-	dir, cleanup, err := makeTempDir("close-double-close")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "doubleclosefile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("first close: %w", err)
-	}
-
-	err = syscall.Close(fd)
-	if err == nil {
-		return fmt.Errorf("expected second close of same fd to fail")
-	}
-	return nil
-}
-
-// closeRangeEmpty calls close_range(2) with a range of very high fd numbers
-// (9000–9999) where no fds are open. The syscall succeeds (empty range is valid),
-// and ior should capture the enter_close_range tracepoint.
-func closeRangeEmpty() error {
-	_, _, errno := syscall.Syscall(sysCloseRange, 9000, 9999, 0)
-	if errno != 0 {
-		return fmt.Errorf("close_range: %w", errno)
-	}
-	return nil
-}
-
-// dupBasic opens a file, dups the fd, writes via the dup, closes both.
-func dupBasic() error {
-	dir, cleanup, err := makeTempDir("dup-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "dupfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	newFd, err := syscall.Dup(fd)
-	if err != nil {
-		return fmt.Errorf("dup: %w", err)
-	}
-	defer syscall.Close(newFd)
-
-	if _, err := syscall.Write(newFd, []byte("via dup")); err != nil {
-		return fmt.Errorf("write via dup: %w", err)
-	}
-	return nil
-}
-
-// dupDup2 opens a file and duplicates the fd onto a specific target fd via dup2.
-func dupDup2() error {
-	dir, cleanup, err := makeTempDir("dup-dup2")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "dup2file.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	// Use a high fd number to avoid collisions.
-	targetFd := 500
-	if err := syscall.Dup2(fd, targetFd); err != nil {
-		return fmt.Errorf("dup2: %w", err)
-	}
-	defer syscall.Close(targetFd)
-
-	if _, err := syscall.Write(targetFd, []byte("via dup2")); err != nil {
-		return fmt.Errorf("write via dup2: %w", err)
-	}
-	return nil
-}
-
-// dupDup3 opens a file and duplicates the fd onto a specific target fd via dup3
-// with O_CLOEXEC flag.
-func dupDup3() error {
-	dir, cleanup, err := makeTempDir("dup-dup3")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "dup3file.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	// Use a high fd number to avoid collisions.
-	targetFd := 501
-	if err := syscall.Dup3(fd, targetFd, syscall.O_CLOEXEC); err != nil {
-		return fmt.Errorf("dup3: %w", err)
-	}
-	defer syscall.Close(targetFd)
-
-	if _, err := syscall.Write(targetFd, []byte("via dup3")); err != nil {
-		return fmt.Errorf("write via dup3: %w", err)
-	}
-	return nil
-}
-
-// dupInvalidFd attempts to dup a very high invalid fd number.
-// The syscall fails with EBADF, but ior should capture the enter_dup
-// tracepoint because arguments are read on syscall entry.
-func dupInvalidFd() error {
-	_, err := syscall.Dup(99999)
-	if err == nil {
-		return fmt.Errorf("expected dup of invalid fd to fail")
-	}
-	return nil
-}
-
-// dup2SameFd calls dup2 with the same fd for both oldfd and newfd.
-// Per POSIX, dup2(fd, fd) is a no-op that returns fd without closing
-// and reopening. ior should capture the enter_dup2 tracepoint.
-func dup2SameFd() error {
-	dir, cleanup, err := makeTempDir("dup2-same-fd")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "dup2samefile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	if err := syscall.Dup2(fd, fd); err != nil {
-		return fmt.Errorf("dup2 same fd: %w", err)
-	}
-	return nil
-}
-
-// dup3InvalidFlags calls dup3 with an invalid flags value.
-// dup3 only accepts O_CLOEXEC; any other flag causes EINVAL.
-// ior should capture the enter_dup3 tracepoint.
-func dup3InvalidFlags() error {
-	dir, cleanup, err := makeTempDir("dup3-invalid-flags")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "dup3flagsfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	targetFd := 502
-	_, _, errno := syscall.Syscall(syscall.SYS_DUP3, uintptr(fd), uintptr(targetFd), 0xBAD)
-	if errno == 0 {
-		syscall.Close(targetFd)
-		return fmt.Errorf("expected dup3 with invalid flags to fail")
-	}
-	return nil
-}
-
-// fcntlDupfd uses fcntl F_DUPFD to duplicate a file descriptor.
-func fcntlDupfd() error {
-	dir, cleanup, err := makeTempDir("fcntl-dupfd")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "fcntlfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	newFd, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_DUPFD, 0)
-	if errno != 0 {
-		return fmt.Errorf("fcntl F_DUPFD: %w", errno)
-	}
-	defer syscall.Close(int(newFd))
-
-	if _, err := syscall.Write(int(newFd), []byte("via fcntl")); err != nil {
-		return fmt.Errorf("write via fcntl dup: %w", err)
-	}
-	return nil
-}
-
-// fcntlSetfl uses fcntl F_GETFL/F_SETFL to read and modify file status flags.
-func fcntlSetfl() error {
-	dir, cleanup, err := makeTempDir("fcntl-setfl")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "fcntlsetflfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	flags, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_GETFL, 0)
-	if errno != 0 {
-		return fmt.Errorf("fcntl F_GETFL: %w", errno)
-	}
-
-	_, _, errno = syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_SETFL, flags|syscall.O_APPEND)
-	if errno != 0 {
-		return fmt.Errorf("fcntl F_SETFL: %w", errno)
-	}
-
-	if _, err := syscall.Write(fd, []byte("appended via fcntl setfl")); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	return nil
-}
-
-// fcntlDupfdCloexec uses fcntl F_DUPFD_CLOEXEC to duplicate a file descriptor
-// with the close-on-exec flag set.
-func fcntlDupfdCloexec() error {
-	dir, cleanup, err := makeTempDir("fcntl-dupfd-cloexec")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "fcntlcloexecfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	newFd, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_DUPFD_CLOEXEC, 0)
-	if errno != 0 {
-		return fmt.Errorf("fcntl F_DUPFD_CLOEXEC: %w", errno)
-	}
-	defer syscall.Close(int(newFd))
-
-	if _, err := syscall.Write(int(newFd), []byte("via fcntl dupfd cloexec")); err != nil {
-		return fmt.Errorf("write via fcntl dup cloexec: %w", err)
-	}
-	return nil
-}
-
-// fcntlInvalidFd calls fcntl F_GETFL on an invalid fd (99999).
-// The syscall fails with EBADF, but ior should capture the enter_fcntl
-// tracepoint because it is recorded on syscall entry.
-func fcntlInvalidFd() error {
-	_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, 99999, syscall.F_GETFL, 0)
-	if errno == 0 {
-		return fmt.Errorf("expected fcntl on invalid fd to fail")
-	}
-	return nil
-}
-
-// fcntlDupfdMax opens a file and calls fcntl F_DUPFD with a minfd value
-// that exceeds the process RLIMIT_NOFILE. The kernel rejects this with
-// EINVAL, but ior should capture the enter_fcntl tracepoint.
-func fcntlDupfdMax() error {
-	dir, cleanup, err := makeTempDir("fcntl-dupfd-max")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "fcntldupfdmaxfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	// Use a minfd far beyond any realistic RLIMIT_NOFILE.
-	_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_DUPFD, 1<<30)
-	if errno == 0 {
-		return fmt.Errorf("expected fcntl F_DUPFD with extreme minfd to fail")
-	}
-	return nil
-}
-
-// renameBasic creates a file and renames it via rename(2).
-// Uses raw SYS_RENAME because Go's syscall.Rename wraps renameat on amd64.
-func renameBasic() error {
-	dir, cleanup, err := makeTempDir("rename-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	oldPath := filepath.Join(dir, "oldname.txt")
-	newPath := filepath.Join(dir, "newname.txt")
-
-	fd, err := syscall.Open(oldPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	oldBytes, err := syscall.BytePtrFromString(oldPath)
-	if err != nil {
-		return fmt.Errorf("old path bytes: %w", err)
-	}
-	newBytes, err := syscall.BytePtrFromString(newPath)
-	if err != nil {
-		return fmt.Errorf("new path bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_RENAME,
-		uintptr(unsafe.Pointer(oldBytes)),
-		uintptr(unsafe.Pointer(newBytes)),
-		0,
-	)
-	runtime.KeepAlive(oldBytes)
-	runtime.KeepAlive(newBytes)
-	if errno != 0 {
-		return fmt.Errorf("rename: %w", errno)
-	}
-	return nil
-}
-
-// renameRenameat creates a file and renames it via renameat(2).
-func renameRenameat() error {
-	dir, cleanup, err := makeTempDir("rename-renameat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	oldName := "renameat-old.txt"
-	newName := "renameat-new.txt"
-	path := filepath.Join(dir, oldName)
-
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	oldBytes, err := syscall.BytePtrFromString(oldName)
-	if err != nil {
-		return fmt.Errorf("old name bytes: %w", err)
-	}
-	newBytes, err := syscall.BytePtrFromString(newName)
-	if err != nil {
-		return fmt.Errorf("new name bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall6(
-		syscall.SYS_RENAMEAT,
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(oldBytes)),
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(newBytes)),
-		0, 0,
-	)
-	runtime.KeepAlive(oldBytes)
-	runtime.KeepAlive(newBytes)
-	if errno != 0 {
-		return fmt.Errorf("renameat: %w", errno)
-	}
-	return nil
-}
-
-const sysRenameat2 = 316 // SYS_RENAMEAT2 on amd64
-
-// renameRenameat2 creates a file and renames it via renameat2(2) with no flags.
-func renameRenameat2() error {
-	dir, cleanup, err := makeTempDir("rename-renameat2")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	oldName := "renameat2-old.txt"
-	newName := "renameat2-new.txt"
-	path := filepath.Join(dir, oldName)
-
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	oldBytes, err := syscall.BytePtrFromString(oldName)
-	if err != nil {
-		return fmt.Errorf("old name bytes: %w", err)
-	}
-	newBytes, err := syscall.BytePtrFromString(newName)
-	if err != nil {
-		return fmt.Errorf("new name bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall6(
-		sysRenameat2,
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(oldBytes)),
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(newBytes)),
-		0, // flags=0: plain rename
-		0,
-	)
-	runtime.KeepAlive(oldBytes)
-	runtime.KeepAlive(newBytes)
-	if errno != 0 {
-		return fmt.Errorf("renameat2: %w", errno)
-	}
-	return nil
-}
-
-// renameEnoent attempts to rename a nonexistent file via raw SYS_RENAME.
-// The syscall fails with ENOENT, but ior captures the tracepoint on entry.
-func renameEnoent() error {
-	dir, cleanup, err := makeTempDir("rename-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	oldPath := filepath.Join(dir, "rename-enoent-missing.txt")
-	newPath := filepath.Join(dir, "rename-enoent-new.txt")
-
-	oldBytes, err := syscall.BytePtrFromString(oldPath)
-	if err != nil {
-		return fmt.Errorf("old path bytes: %w", err)
-	}
-	newBytes, err := syscall.BytePtrFromString(newPath)
-	if err != nil {
-		return fmt.Errorf("new path bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_RENAME,
-		uintptr(unsafe.Pointer(oldBytes)),
-		uintptr(unsafe.Pointer(newBytes)),
-		0,
-	)
-	runtime.KeepAlive(oldBytes)
-	runtime.KeepAlive(newBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but rename succeeded")
-	}
-	return nil
-}
-
-const renameNoreplaceFlag = 1 // RENAME_NOREPLACE
-
-// renameNoreplace creates two files, then attempts renameat2 with
-// RENAME_NOREPLACE. Because the target already exists, the syscall fails
-// with EEXIST, but ior captures the tracepoint on entry.
-func renameNoreplace() error {
-	dir, cleanup, err := makeTempDir("rename-noreplace")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	srcName := "noreplace-src.txt"
-	dstName := "noreplace-dst.txt"
-
-	for _, name := range []string{srcName, dstName} {
-		path := filepath.Join(dir, name)
-		fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-		if err != nil {
-			return fmt.Errorf("create %s: %w", name, err)
-		}
-		if err := syscall.Close(fd); err != nil {
-			return fmt.Errorf("close %s: %w", name, err)
-		}
-	}
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	srcBytes, err := syscall.BytePtrFromString(srcName)
-	if err != nil {
-		return fmt.Errorf("src name bytes: %w", err)
-	}
-	dstBytes, err := syscall.BytePtrFromString(dstName)
-	if err != nil {
-		return fmt.Errorf("dst name bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall6(
-		sysRenameat2,
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(srcBytes)),
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(dstBytes)),
-		renameNoreplaceFlag,
-		0,
-	)
-	runtime.KeepAlive(srcBytes)
-	runtime.KeepAlive(dstBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected EEXIST, but renameat2 NOREPLACE succeeded")
-	}
-	return nil
-}
-
-// linkBasic creates a file, hard links it via link(2), symlinks it via
-// symlink(2), and reads the symlink via readlink(2).
-// Uses raw SYS_LINK, SYS_SYMLINK, SYS_READLINK because Go's syscall wrappers
-// delegate to linkat/symlinkat/readlinkat on amd64.
-func linkBasic() error {
-	dir, cleanup, err := makeTempDir("link-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	origPath := filepath.Join(dir, "original.txt")
-	fd, err := syscall.Open(origPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	// Hard link via raw SYS_LINK.
-	hardPath := filepath.Join(dir, "hardlink.txt")
-	origBytes, err := syscall.BytePtrFromString(origPath)
-	if err != nil {
-		return fmt.Errorf("orig path bytes: %w", err)
-	}
-	hardBytes, err := syscall.BytePtrFromString(hardPath)
-	if err != nil {
-		return fmt.Errorf("hard path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_LINK,
-		uintptr(unsafe.Pointer(origBytes)),
-		uintptr(unsafe.Pointer(hardBytes)),
-		0,
-	)
-	runtime.KeepAlive(origBytes)
-	runtime.KeepAlive(hardBytes)
-	if errno != 0 {
-		return fmt.Errorf("link: %w", errno)
-	}
-
-	// Symlink via raw SYS_SYMLINK.
-	symPath := filepath.Join(dir, "symlink.txt")
-	targetBytes, err := syscall.BytePtrFromString(origPath)
-	if err != nil {
-		return fmt.Errorf("target path bytes: %w", err)
-	}
-	symBytes, err := syscall.BytePtrFromString(symPath)
-	if err != nil {
-		return fmt.Errorf("sym path bytes: %w", err)
-	}
-	_, _, errno = syscall.Syscall(
-		syscall.SYS_SYMLINK,
-		uintptr(unsafe.Pointer(targetBytes)),
-		uintptr(unsafe.Pointer(symBytes)),
-		0,
-	)
-	runtime.KeepAlive(targetBytes)
-	runtime.KeepAlive(symBytes)
-	if errno != 0 {
-		return fmt.Errorf("symlink: %w", errno)
-	}
-
-	// Readlink via raw SYS_READLINK.
-	symBytes2, err := syscall.BytePtrFromString(symPath)
-	if err != nil {
-		return fmt.Errorf("sym path bytes: %w", err)
-	}
-	buf := make([]byte, 256)
-	_, _, errno = syscall.Syscall(
-		syscall.SYS_READLINK,
-		uintptr(unsafe.Pointer(symBytes2)),
-		uintptr(unsafe.Pointer(&buf[0])),
-		uintptr(len(buf)),
-	)
-	runtime.KeepAlive(symBytes2)
-	runtime.KeepAlive(buf)
-	if errno != 0 {
-		return fmt.Errorf("readlink: %w", errno)
-	}
-	return nil
-}
-
-// linkLinkat creates a file and hard links it via linkat(2).
-func linkLinkat() error {
-	dir, cleanup, err := makeTempDir("link-linkat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	origName := "linkat-original.txt"
-	origPath := filepath.Join(dir, origName)
-	fd, err := syscall.Open(origPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	hardName := "linkat-hard.txt"
-	oldBytes, err := syscall.BytePtrFromString(origName)
-	if err != nil {
-		return fmt.Errorf("old name bytes: %w", err)
-	}
-	newBytes, err := syscall.BytePtrFromString(hardName)
-	if err != nil {
-		return fmt.Errorf("new name bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall6(
-		syscall.SYS_LINKAT,
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(oldBytes)),
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(newBytes)),
-		0, // flags
-		0,
-	)
-	runtime.KeepAlive(oldBytes)
-	runtime.KeepAlive(newBytes)
-	if errno != 0 {
-		return fmt.Errorf("linkat: %w", errno)
-	}
-	return nil
-}
-
-// linkSymlinkat creates a symlink via symlinkat(2).
-func linkSymlinkat() error {
-	dir, cleanup, err := makeTempDir("link-symlinkat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	origPath := filepath.Join(dir, "symlinkat-original.txt")
-	fd, err := syscall.Open(origPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	targetBytes, err := syscall.BytePtrFromString(origPath)
-	if err != nil {
-		return fmt.Errorf("target bytes: %w", err)
-	}
-	linkName := "symlinkat-link.txt"
-	linkBytes, err := syscall.BytePtrFromString(linkName)
-	if err != nil {
-		return fmt.Errorf("link name bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_SYMLINKAT,
-		uintptr(unsafe.Pointer(targetBytes)),
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(linkBytes)),
-	)
-	runtime.KeepAlive(targetBytes)
-	runtime.KeepAlive(linkBytes)
-	if errno != 0 {
-		return fmt.Errorf("symlinkat: %w", errno)
-	}
-	return nil
-}
-
-// linkReadlinkat creates a symlink, then reads it via readlinkat(2).
-func linkReadlinkat() error {
-	dir, cleanup, err := makeTempDir("link-readlinkat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	origPath := filepath.Join(dir, "readlinkat-original.txt")
-	fd, err := syscall.Open(origPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	// Create symlink using raw SYS_SYMLINK so we don't mix tracepoints.
-	linkPath := filepath.Join(dir, "readlinkat-link.txt")
-	targetBytes, err := syscall.BytePtrFromString(origPath)
-	if err != nil {
-		return fmt.Errorf("target bytes: %w", err)
-	}
-	linkPathBytes, err := syscall.BytePtrFromString(linkPath)
-	if err != nil {
-		return fmt.Errorf("link path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_SYMLINK,
-		uintptr(unsafe.Pointer(targetBytes)),
-		uintptr(unsafe.Pointer(linkPathBytes)),
-		0,
-	)
-	runtime.KeepAlive(targetBytes)
-	runtime.KeepAlive(linkPathBytes)
-	if errno != 0 {
-		return fmt.Errorf("symlink: %w", errno)
-	}
-
-	// Read via readlinkat(2).
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	linkName := "readlinkat-link.txt"
-	nameBytes, err := syscall.BytePtrFromString(linkName)
-	if err != nil {
-		return fmt.Errorf("link name bytes: %w", err)
-	}
-	buf := make([]byte, 256)
-	_, _, errno = syscall.Syscall6(
-		syscall.SYS_READLINKAT,
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(nameBytes)),
-		uintptr(unsafe.Pointer(&buf[0])),
-		uintptr(len(buf)),
-		0, 0,
-	)
-	runtime.KeepAlive(nameBytes)
-	runtime.KeepAlive(buf)
-	if errno != 0 {
-		return fmt.Errorf("readlinkat: %w", errno)
-	}
-	return nil
-}
-
-// linkEnoent attempts to hard link a nonexistent source via raw SYS_LINK.
-// The syscall fails with ENOENT, but ior captures the enter_link tracepoint
-// because arguments are read on syscall entry.
-func linkEnoent() error {
-	dir, cleanup, err := makeTempDir("link-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	srcPath := filepath.Join(dir, "link-enoent-missing.txt")
-	dstPath := filepath.Join(dir, "link-enoent-dst.txt")
-
-	srcBytes, err := syscall.BytePtrFromString(srcPath)
-	if err != nil {
-		return fmt.Errorf("src path bytes: %w", err)
-	}
-	dstBytes, err := syscall.BytePtrFromString(dstPath)
-	if err != nil {
-		return fmt.Errorf("dst path bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_LINK,
-		uintptr(unsafe.Pointer(srcBytes)),
-		uintptr(unsafe.Pointer(dstBytes)),
-		0,
-	)
-	runtime.KeepAlive(srcBytes)
-	runtime.KeepAlive(dstBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but link succeeded")
-	}
-	return nil
-}
-
-// linkSymlinkEexist creates a regular file, then attempts to create a symlink
-// at the same path via raw SYS_SYMLINK. The syscall fails with EEXIST because
-// the link path already exists, but ior captures the enter_symlink tracepoint.
-func linkSymlinkEexist() error {
-	dir, cleanup, err := makeTempDir("link-symlink-eexist")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	existingPath := filepath.Join(dir, "symlink-eexist.txt")
-	fd, err := syscall.Open(existingPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	targetBytes, err := syscall.BytePtrFromString("/tmp/dummy-target")
-	if err != nil {
-		return fmt.Errorf("target bytes: %w", err)
-	}
-	linkBytes, err := syscall.BytePtrFromString(existingPath)
-	if err != nil {
-		return fmt.Errorf("link path bytes: %w", err)
-	}
-
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_SYMLINK,
-		uintptr(unsafe.Pointer(targetBytes)),
-		uintptr(unsafe.Pointer(linkBytes)),
-		0,
-	)
-	runtime.KeepAlive(targetBytes)
-	runtime.KeepAlive(linkBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected EEXIST, but symlink succeeded")
-	}
-	return nil
-}
-
-// linkReadlinkatEinval creates a regular file and calls readlinkat(2) on it.
-// The syscall fails with EINVAL because the path is not a symlink, but ior
-// captures the enter_readlinkat tracepoint on syscall entry.
-func linkReadlinkatEinval() error {
-	dir, cleanup, err := makeTempDir("link-readlinkat-einval")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	regularFile := "readlinkat-einval.txt"
-	regularPath := filepath.Join(dir, regularFile)
-	fd, err := syscall.Open(regularPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	nameBytes, err := syscall.BytePtrFromString(regularFile)
-	if err != nil {
-		return fmt.Errorf("name bytes: %w", err)
-	}
-	buf := make([]byte, 256)
-	_, _, errno := syscall.Syscall6(
-		syscall.SYS_READLINKAT,
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(nameBytes)),
-		uintptr(unsafe.Pointer(&buf[0])),
-		uintptr(len(buf)),
-		0, 0,
-	)
-	runtime.KeepAlive(nameBytes)
-	runtime.KeepAlive(buf)
-	if errno == 0 {
-		return fmt.Errorf("expected EINVAL, but readlinkat succeeded")
-	}
-	return nil
-}
-
-// unlinkBasic creates a file and unlinks it via raw SYS_UNLINK.
-// We use the raw syscall because Go's syscall.Unlink wraps unlinkat on amd64.
-func unlinkBasic() error {
-	dir, cleanup, err := makeTempDir("unlink-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "unlinkme.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_UNLINK, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno != 0 {
-		return fmt.Errorf("unlink: %w", errno)
-	}
-	return nil
-}
-
-// unlinkUnlinkat creates a file and unlinks it via unlinkat(2).
-func unlinkUnlinkat() error {
-	dir, cleanup, err := makeTempDir("unlink-unlinkat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "unlinkat-file.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	nameBytes, err := syscall.BytePtrFromString("unlinkat-file.txt")
-	if err != nil {
-		return fmt.Errorf("name bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_UNLINKAT, uintptr(dirFD), uintptr(unsafe.Pointer(nameBytes)), 0)
-	runtime.KeepAlive(nameBytes)
-	if errno != 0 {
-		return fmt.Errorf("unlinkat: %w", errno)
-	}
-	return nil
-}
-
-// unlinkRmdir creates a directory and removes it via raw SYS_RMDIR.
-// We use the raw syscall because Go's syscall.Rmdir wraps unlinkat on amd64.
-func unlinkRmdir() error {
-	dir, cleanup, err := makeTempDir("unlink-rmdir")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	subDir := filepath.Join(dir, "rmdir-me")
-	if err := syscall.Mkdir(subDir, 0o755); err != nil {
-		return fmt.Errorf("mkdir: %w", err)
-	}
-
-	pathBytes, err := syscall.BytePtrFromString(subDir)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_RMDIR, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno != 0 {
-		return fmt.Errorf("rmdir: %w", errno)
-	}
-	return nil
-}
-
-// unlinkEnoent attempts to unlink a nonexistent file via raw SYS_UNLINK.
-// The syscall fails with ENOENT, but ior captures the tracepoint on entry.
-func unlinkEnoent() error {
-	dir, cleanup, err := makeTempDir("unlink-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "unlink-enoent-missing.txt")
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_UNLINK, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but unlink succeeded")
-	}
-	return nil
-}
-
-// unlinkRmdirNotempty attempts to rmdir a non-empty directory via raw SYS_RMDIR.
-// The syscall fails with ENOTEMPTY, but ior captures the tracepoint on entry.
-func unlinkRmdirNotempty() error {
-	dir, cleanup, err := makeTempDir("unlink-rmdir-notempty")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	subDir := filepath.Join(dir, "rmdir-notempty")
-	if err := syscall.Mkdir(subDir, 0o755); err != nil {
-		return fmt.Errorf("mkdir: %w", err)
-	}
-
-	// Create a file inside so the directory is non-empty.
-	filePath := filepath.Join(subDir, "blocker.txt")
-	fd, err := syscall.Open(filePath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("create blocker: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close blocker: %w", err)
-	}
-
-	pathBytes, err := syscall.BytePtrFromString(subDir)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_RMDIR, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOTEMPTY, but rmdir succeeded")
-	}
-	return nil
-}
-
-// unlinkUnlinkatEnoent attempts to unlinkat a nonexistent file.
-// The syscall fails with ENOENT, but ior captures the tracepoint on entry.
-func unlinkUnlinkatEnoent() error {
-	dir, cleanup, err := makeTempDir("unlink-unlinkat-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	nameBytes, err := syscall.BytePtrFromString("unlinkat-enoent-missing.txt")
-	if err != nil {
-		return fmt.Errorf("name bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_UNLINKAT, uintptr(dirFD), uintptr(unsafe.Pointer(nameBytes)), 0)
-	runtime.KeepAlive(nameBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but unlinkat succeeded")
-	}
-	return nil
-}
-
-// dirBasic creates a directory via raw SYS_MKDIR, checks access, then removes it
-// via raw SYS_RMDIR. We use raw syscalls because Go's syscall.Mkdir wraps mkdirat
-// and syscall.Rmdir wraps unlinkat on amd64.
-func dirBasic() error {
-	dir, cleanup, err := makeTempDir("dir-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	subDir := filepath.Join(dir, "subdir")
-	pathBytes, err := syscall.BytePtrFromString(subDir)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_MKDIR, uintptr(unsafe.Pointer(pathBytes)), 0o755, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno != 0 {
-		return fmt.Errorf("mkdir: %w", errno)
-	}
-
-	if err := syscall.Access(subDir, syscall.F_OK); err != nil {
-		return fmt.Errorf("access: %w", err)
-	}
-
-	pathBytes2, err := syscall.BytePtrFromString(subDir)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno = syscall.Syscall(syscall.SYS_RMDIR, uintptr(unsafe.Pointer(pathBytes2)), 0, 0)
-	runtime.KeepAlive(pathBytes2)
-	if errno != 0 {
-		return fmt.Errorf("rmdir: %w", errno)
-	}
-	return nil
-}
-
-// dirMkdirat creates a directory via mkdirat(2) using Go's syscall.Mkdir
-// which wraps mkdirat with AT_FDCWD on amd64.
-func dirMkdirat() error {
-	dir, cleanup, err := makeTempDir("dir-mkdirat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	subDir := filepath.Join(dir, "mkdirat-subdir")
-	if err := syscall.Mkdir(subDir, 0o755); err != nil {
-		return fmt.Errorf("mkdirat: %w", err)
-	}
-	return nil
-}
-
-// dirChdir creates a temp directory, then changes to it via chdir(2).
-// Restores the original working directory afterward.
-func dirChdir() error {
-	origDir, err := os.Getwd()
-	if err != nil {
-		return fmt.Errorf("getwd: %w", err)
-	}
-
-	dir, cleanup, err := makeTempDir("dir-chdir")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-	defer syscall.Chdir(origDir)
-
-	if err := syscall.Chdir(dir); err != nil {
-		return fmt.Errorf("chdir: %w", err)
-	}
-	return nil
-}
-
-// dirGetdents opens a directory and reads its entries via getdents64(2).
-func dirGetdents() error {
-	dir, cleanup, err := makeTempDir("dir-getdents")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	// Create a file so getdents has something to return.
-	filePath := filepath.Join(dir, "getdents-file.txt")
-	fd, err := syscall.Open(filePath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open file: %w", err)
-	}
-	syscall.Close(fd)
-
-	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return fmt.Errorf("open dir: %w", err)
-	}
-	defer syscall.Close(dirFD)
-
-	buf := make([]byte, 4096)
-	_, _, errno := syscall.Syscall(syscall.SYS_GETDENTS64, uintptr(dirFD), uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)))
-	runtime.KeepAlive(buf)
-	if errno != 0 {
-		return fmt.Errorf("getdents64: %w", errno)
-	}
-	return nil
-}
-
-// dirMkdirEexist attempts to create a directory that already exists via raw
-// SYS_MKDIR. The syscall fails with EEXIST, but ior captures the tracepoint
-// on entry.
-func dirMkdirEexist() error {
-	dir, cleanup, err := makeTempDir("dir-mkdir-eexist")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	subDir := filepath.Join(dir, "mkdir-eexist-subdir")
-	pathBytes, err := syscall.BytePtrFromString(subDir)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-
-	// Create the directory first so the second attempt fails.
-	_, _, errno := syscall.Syscall(syscall.SYS_MKDIR, uintptr(unsafe.Pointer(pathBytes)), 0o755, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno != 0 {
-		return fmt.Errorf("first mkdir: %w", errno)
-	}
-
-	// Second mkdir on the same path should fail with EEXIST.
-	pathBytes2, err := syscall.BytePtrFromString(subDir)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno = syscall.Syscall(syscall.SYS_MKDIR, uintptr(unsafe.Pointer(pathBytes2)), 0o755, 0)
-	runtime.KeepAlive(pathBytes2)
-	if errno == 0 {
-		return fmt.Errorf("expected EEXIST, but mkdir succeeded")
-	}
-	return nil
-}
-
-// dirChdirEnoent attempts to change to a nonexistent directory via raw
-// SYS_CHDIR. The syscall fails with ENOENT, but ior captures the tracepoint
-// on entry.
-func dirChdirEnoent() error {
-	dir, cleanup, err := makeTempDir("dir-chdir-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	badPath := filepath.Join(dir, "chdir-enoent-missing")
-	pathBytes, err := syscall.BytePtrFromString(badPath)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_CHDIR, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but chdir succeeded")
-	}
-	return nil
-}
-
-// dirGetdentsEbadf calls getdents64(2) with an invalid file descriptor.
-// The syscall fails with EBADF, but ior captures the tracepoint on entry.
-func dirGetdentsEbadf() error {
-	buf := make([]byte, 4096)
-	_, _, errno := syscall.Syscall(syscall.SYS_GETDENTS64, uintptr(9999), uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)))
-	runtime.KeepAlive(buf)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but getdents64 succeeded")
-	}
-	return nil
-}
-
-// statBasic creates a file and stats it via raw SYS_STAT (newstat).
-// We use the raw syscall because Go's syscall.Stat wraps newfstatat on amd64.
-func statBasic() error {
-	dir, cleanup, err := makeTempDir("stat-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "statfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	syscall.Close(fd)
-
-	var stat syscall.Stat_t
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_STAT, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(&stat)), 0)
-	runtime.KeepAlive(pathBytes)
-	runtime.KeepAlive(&stat)
-	if errno != 0 {
-		return fmt.Errorf("stat: %w", errno)
-	}
-	return nil
-}
-
-// statFstat creates a file and stats it via raw SYS_FSTAT (newfstat).
-// This is an fd_event, so ior resolves the path via its fd lookup table.
-func statFstat() error {
-	dir, cleanup, err := makeTempDir("stat-fstat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "fstatfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	var stat syscall.Stat_t
-	_, _, errno := syscall.Syscall(syscall.SYS_FSTAT, uintptr(fd), uintptr(unsafe.Pointer(&stat)), 0)
-	runtime.KeepAlive(&stat)
-	if errno != 0 {
-		return fmt.Errorf("fstat: %w", errno)
-	}
-	return nil
-}
-
-// statLstat creates a file and stats it via raw SYS_LSTAT (newlstat).
-// We use the raw syscall because Go's syscall.Lstat wraps newfstatat on amd64.
-func statLstat() error {
-	dir, cleanup, err := makeTempDir("stat-lstat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "lstatfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	syscall.Close(fd)
-
-	var stat syscall.Stat_t
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_LSTAT, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(&stat)), 0)
-	runtime.KeepAlive(pathBytes)
-	runtime.KeepAlive(&stat)
-	if errno != 0 {
-		return fmt.Errorf("lstat: %w", errno)
-	}
-	return nil
-}
-
-// statNewfstatat creates a file and stats it via Go's syscall.Stat, which
-// wraps SYS_NEWFSTATAT (fstatat with AT_FDCWD) on amd64.
-func statNewfstatat() error {
-	dir, cleanup, err := makeTempDir("stat-newfstatat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "fstatatfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	syscall.Close(fd)
-
-	var stat syscall.Stat_t
-	if err := syscall.Stat(path, &stat); err != nil {
-		return fmt.Errorf("newfstatat: %w", err)
-	}
-	return nil
-}
-
-const (
-	sysStatx       = 332
-	rOK            = 0x4   // R_OK
-	statxBasicMask = 0x07ff // STATX_BASIC_STATS
-)
-
-const atFDCwd = -100 // AT_FDCWD
-
-// statStatx creates a file and stats it via raw statx(2) syscall.
-func statStatx() error {
-	dir, cleanup, err := makeTempDir("stat-statx")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "statxfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	syscall.Close(fd)
-
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	var buf [256]byte // statx struct is ~256 bytes
-	_, _, errno := syscall.Syscall6(
-		sysStatx,
-		^uintptr(99), // AT_FDCWD (-100)
-		uintptr(unsafe.Pointer(pathBytes)),
-		0,
-		statxBasicMask,
-		uintptr(unsafe.Pointer(&buf[0])),
-		0,
-	)
-	runtime.KeepAlive(pathBytes)
-	runtime.KeepAlive(buf)
-	if errno != 0 {
-		return fmt.Errorf("statx: %w", errno)
-	}
-	return nil
-}
-
-// statAccess creates a file and checks access via raw SYS_ACCESS.
-// We use the raw syscall because Go's syscall.Access wraps faccessat on amd64.
-func statAccess() error {
-	dir, cleanup, err := makeTempDir("stat-access")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "accessfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	syscall.Close(fd)
-
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_ACCESS, uintptr(unsafe.Pointer(pathBytes)), rOK, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno != 0 {
-		return fmt.Errorf("access: %w", errno)
-	}
-	return nil
-}
-
-// statFaccessat creates a file and checks access via faccessat(2).
-// Go's syscall.Faccessat wraps SYS_FACCESSAT.
-func statFaccessat() error {
-	dir, cleanup, err := makeTempDir("stat-faccessat")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "faccessatfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	syscall.Close(fd)
-
-	if err := syscall.Faccessat(atFDCwd, path, uint32(rOK), 0); err != nil {
-		return fmt.Errorf("faccessat: %w", err)
-	}
-	return nil
-}
-
-// statEnoent attempts to stat a nonexistent file via raw SYS_STAT.
-// The syscall fails with ENOENT, but ior captures the enter_newstat
-// tracepoint because the filename is read on entry.
-func statEnoent() error {
-	dir, cleanup, err := makeTempDir("stat-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "stat-enoent-missing.txt")
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	var stat syscall.Stat_t
-	_, _, errno := syscall.Syscall(syscall.SYS_STAT, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(&stat)), 0)
-	runtime.KeepAlive(pathBytes)
-	runtime.KeepAlive(&stat)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but stat succeeded")
-	}
-	return nil
-}
-
-// statAccessEnoent attempts to check access on a nonexistent file via raw
-// SYS_ACCESS. The syscall fails with ENOENT, but ior captures the
-// enter_access tracepoint because the path is read on entry.
-// We use ENOENT instead of EACCES because integration tests run as root,
-// which bypasses DAC permission checks.
-func statAccessEnoent() error {
-	dir, cleanup, err := makeTempDir("stat-access-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "access-enoent-missing.txt")
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_ACCESS, uintptr(unsafe.Pointer(pathBytes)), rOK, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but access succeeded")
-	}
-	return nil
-}
-
-// statFstatEbadf calls raw SYS_FSTAT on an invalid fd (99999).
-// The syscall fails with EBADF, but ior captures the enter_newfstat
-// tracepoint because it is recorded on syscall entry.
-func statFstatEbadf() error {
-	var stat syscall.Stat_t
-	_, _, errno := syscall.Syscall(syscall.SYS_FSTAT, 99999, uintptr(unsafe.Pointer(&stat)), 0)
-	runtime.KeepAlive(&stat)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but fstat succeeded")
-	}
-	return nil
-}
-
-// syncBasic opens a file, writes data, and fsyncs it.
-func syncBasic() error {
-	dir, cleanup, err := makeTempDir("sync-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "syncfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	if _, err := syscall.Write(fd, []byte("sync me")); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	return syscall.Fsync(fd)
-}
-
-// syncFdatasync opens a file, writes data, and fdatasyncs it.
-func syncFdatasync() error {
-	dir, cleanup, err := makeTempDir("sync-fdatasync")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "fdatasyncfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	if _, err := syscall.Write(fd, []byte("fdatasync me")); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	return syscall.Fdatasync(fd)
-}
-
-// syncSync calls sync(2) to flush all filesystem caches.
-// sync is a null_event with no file arguments.
-func syncSync() error {
-	syscall.Sync()
-	return nil
-}
-
-// syncSyncFileRange opens a file, writes data, then calls sync_file_range(2).
-func syncSyncFileRange() error {
-	dir, cleanup, err := makeTempDir("sync-sync-file-range")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "syncrangefile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	data := []byte("sync file range data")
-	if _, err := syscall.Write(fd, data); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	return syscall.SyncFileRange(fd, 0, int64(len(data)), 0)
-}
-
-// syncFsyncEbadf calls fsync on an invalid fd.
-// The syscall fails with EBADF, but ior captures the enter_fsync tracepoint.
-func syncFsyncEbadf() error {
-	_, _, errno := syscall.Syscall(syscall.SYS_FSYNC, 99999, 0, 0)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but fsync succeeded")
-	}
-	return nil
-}
-
-// syncFdatasyncEbadf calls fdatasync on an invalid fd.
-// The syscall fails with EBADF, but ior captures the enter_fdatasync tracepoint.
-func syncFdatasyncEbadf() error {
-	_, _, errno := syscall.Syscall(syscall.SYS_FDATASYNC, 99999, 0, 0)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but fdatasync succeeded")
-	}
-	return nil
-}
-
-// syncFileRangeEbadf calls sync_file_range on an invalid fd.
-// The syscall fails with EBADF, but ior captures the enter_sync_file_range tracepoint.
-func syncFileRangeEbadf() error {
-	_, _, errno := syscall.Syscall6(syscall.SYS_SYNC_FILE_RANGE, 99999, 0, 0, 0, 0, 0)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but sync_file_range succeeded")
-	}
-	return nil
-}
-
-// truncateBasic opens a file, writes data, then truncates it via
-// syscall.Truncate which uses SYS_TRUNCATE directly on amd64 (path-based).
-func truncateBasic() error {
-	dir, cleanup, err := makeTempDir("truncate-basic")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "truncfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-
-	if _, err := syscall.Write(fd, []byte("truncate this content")); err != nil {
-		syscall.Close(fd)
-		return fmt.Errorf("write: %w", err)
-	}
-	syscall.Close(fd)
-
-	return syscall.Truncate(path, 5)
-}
-
-// truncateFtruncate opens a file, writes data, then truncates it via
-// syscall.Ftruncate which uses SYS_FTRUNCATE directly on amd64 (fd-based).
-func truncateFtruncate() error {
-	dir, cleanup, err := makeTempDir("truncate-ftruncate")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "ftruncfile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	defer syscall.Close(fd)
-
-	if _, err := syscall.Write(fd, []byte("ftruncate this content")); err != nil {
-		return fmt.Errorf("write: %w", err)
-	}
-	return syscall.Ftruncate(fd, 5)
-}
-
-// truncateEnoent attempts to truncate a nonexistent file via raw SYS_TRUNCATE.
-// The syscall fails with ENOENT, but ior captures the enter_truncate
-// tracepoint because the path is read on entry.
-func truncateEnoent() error {
-	dir, cleanup, err := makeTempDir("truncate-enoent")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "truncate-enoent-missing.txt")
-	pathBytes, err := syscall.BytePtrFromString(path)
-	if err != nil {
-		return fmt.Errorf("path bytes: %w", err)
-	}
-	_, _, errno := syscall.Syscall(syscall.SYS_TRUNCATE, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
-	runtime.KeepAlive(pathBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but truncate succeeded")
-	}
-	return nil
-}
-
-// truncateFtruncateEbadf calls raw SYS_FTRUNCATE on an invalid fd (99999).
-// The syscall fails with EBADF, but ior captures the enter_ftruncate
-// tracepoint because it is recorded on syscall entry.
-func truncateFtruncateEbadf() error {
-	_, _, errno := syscall.Syscall(syscall.SYS_FTRUNCATE, 99999, 0, 0)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but ftruncate succeeded")
-	}
-	return nil
-}
-
-// openByHandleAt creates a file, resolves its handle via name_to_handle_at,
-// then opens it via open_by_handle_at. Requires root (CAP_DAC_READ_SEARCH).
-// LockOSThread prevents goroutine migration between the two syscalls so that
-// ior sees the same TID for both and can correlate the path.
-func openByHandleAt() error {
-	runtime.LockOSThread()
-	defer runtime.UnlockOSThread()
-
-	dir, cleanup, err := makeTempDir("open-by-handle-at")
-	if err != nil {
-		return err
-	}
-	defer cleanup()
-
-	path := filepath.Join(dir, "handlefile.txt")
-	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
-	if err != nil {
-		return fmt.Errorf("open: %w", err)
-	}
-	if err := syscall.Close(fd); err != nil {
-		return fmt.Errorf("close: %w", err)
-	}
-
-	handle, mountFD, err := nameToHandleAt(dir, "handlefile.txt")
-	if err != nil {
-		return fmt.Errorf("name_to_handle_at: %w", err)
-	}
-	defer syscall.Close(mountFD)
-
-	fd2, err := openByHandleAtSyscall(mountFD, handle, syscall.O_RDONLY)
-	if err != nil {
-		return fmt.Errorf("open_by_handle_at: %w", err)
-	}
-	return syscall.Close(fd2)
-}
-
-// fileHandle matches the kernel's struct file_handle layout.
-type fileHandle struct {
-	Size uint32
-	Type int32
-	// Handle bytes follow immediately after.
-}
-
-const (
-	sysNameToHandleAt = 303
-	sysOpenByHandleAt = 304
-)
-
-// nameToHandleAt calls name_to_handle_at(2) and returns the file handle
-// and the directory fd. The caller can pass this dirFD as the mount_fd
-// argument to open_by_handle_at since any fd on the same filesystem works.
-func nameToHandleAt(dirPath, name string) ([]byte, int, error) {
-	dirFD, err := syscall.Open(dirPath, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
-	if err != nil {
-		return nil, 0, fmt.Errorf("open dir: %w", err)
-	}
-
-	nameBytes, err := syscall.BytePtrFromString(name)
-	if err != nil {
-		syscall.Close(dirFD)
-		return nil, 0, fmt.Errorf("name bytes: %w", err)
-	}
-
-	// Start with a buffer large enough for most handles.
-	buf := make([]byte, unsafe.Sizeof(fileHandle{})+128)
-	fh := (*fileHandle)(unsafe.Pointer(&buf[0]))
-	fh.Size = uint32(len(buf) - int(unsafe.Sizeof(fileHandle{})))
-
-	var mountID int32
-	_, _, errno := syscall.Syscall6(
-		sysNameToHandleAt,
-		uintptr(dirFD),
-		uintptr(unsafe.Pointer(nameBytes)),
-		uintptr(unsafe.Pointer(fh)),
-		uintptr(unsafe.Pointer(&mountID)),
-		0, 0,
-	)
-	if errno != 0 {
-		syscall.Close(dirFD)
-		return nil, 0, fmt.Errorf("syscall: %w", errno)
-	}
-
-	handleLen := int(unsafe.Sizeof(fileHandle{})) + int(fh.Size)
-	handle := make([]byte, handleLen)
-	copy(handle, buf[:handleLen])
-
-	return handle, dirFD, nil
-}
-
-// openByHandleAtSyscall calls open_by_handle_at(2).
-func openByHandleAtSyscall(mountFD int, handle []byte, flags int) (int, error) {
-	fd, _, errno := syscall.Syscall(
-		sysOpenByHandleAt,
-		uintptr(mountFD),
-		uintptr(unsafe.Pointer(&handle[0])),
-		uintptr(flags),
-	)
-	if errno != 0 {
-		return 0, fmt.Errorf("syscall: %w", errno)
-	}
-	return int(fd), nil
-}
-
-const (
-	sysIoUringSetup    = 425
-	sysIoUringEnter    = 426
-	sysIoUringRegister = 427
-
-	// io_uring_params struct size: 10 x uint32 + io_sqring_offsets(40) + io_cqring_offsets(40) = 120 bytes.
-	ioUringParamsSize = 120
-
-	ioringRegisterProbe = 8 // IORING_REGISTER_PROBE
-)
-
-// iouringSetup creates an io_uring instance via io_uring_setup(2) and closes the fd.
-func iouringSetup() error {
-	fd, err := ioUringSetupRing(1)
-	if err != nil {
-		return err
-	}
-	return syscall.Close(fd)
-}
-
-// iouringEnter creates an io_uring instance, then calls io_uring_enter(2)
-// with zero submissions/completions to exercise the enter tracepoint.
-func iouringEnter() error {
-	fd, err := ioUringSetupRing(1)
-	if err != nil {
-		return err
-	}
-	defer syscall.Close(fd)
-
-	_, _, errno := syscall.Syscall6(
-		sysIoUringEnter,
-		uintptr(fd),
-		0, // to_submit
-		0, // min_complete
-		0, // flags
-		0, // sig
-		0, // sz
-	)
-	if errno != 0 {
-		return fmt.Errorf("io_uring_enter: %w", errno)
-	}
-	return nil
-}
-
-// iouringRegister creates an io_uring instance, then calls io_uring_register(2)
-// with IORING_REGISTER_PROBE to exercise the register tracepoint.
-func iouringRegister() error {
-	fd, err := ioUringSetupRing(1)
-	if err != nil {
-		return err
-	}
-	defer syscall.Close(fd)
-
-	// io_uring_probe header is 16 bytes; we don't need probe_op entries.
-	var probeBuf [16]byte
-	_, _, errno := syscall.Syscall6(
-		sysIoUringRegister,
-		uintptr(fd),
-		ioringRegisterProbe,
-		uintptr(unsafe.Pointer(&probeBuf[0])),
-		0, // nr_args (0 ops requested)
-		0, 0,
-	)
-	runtime.KeepAlive(probeBuf)
-	if errno != 0 {
-		return fmt.Errorf("io_uring_register: %w", errno)
-	}
-	return nil
-}
-
-// iouringEnterEbadf calls io_uring_enter on an invalid fd.
-// The syscall fails with EBADF, but ior captures the enter_io_uring_enter tracepoint.
-func iouringEnterEbadf() error {
-	_, _, errno := syscall.Syscall6(
-		sysIoUringEnter,
-		99999, // invalid fd
-		0,     // to_submit
-		0,     // min_complete
-		0,     // flags
-		0,     // sig
-		0,     // sz
-	)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but io_uring_enter succeeded")
-	}
-	return nil
-}
-
-// iouringRegisterEbadf calls io_uring_register on an invalid fd.
-// The syscall fails with EBADF, but ior captures the enter_io_uring_register tracepoint.
-func iouringRegisterEbadf() error {
-	_, _, errno := syscall.Syscall6(
-		sysIoUringRegister,
-		99999,             // invalid fd
-		ioringRegisterProbe,
-		0,                 // arg (NULL)
-		0,                 // nr_args
-		0, 0,
-	)
-	if errno == 0 {
-		return fmt.Errorf("expected EBADF, but io_uring_register succeeded")
-	}
-	return nil
-}
-
-// ioUringSetupRing calls io_uring_setup(2) and returns the ring fd.
-func ioUringSetupRing(entries uint32) (int, error) {
-	var params [ioUringParamsSize]byte
-	fd, _, errno := syscall.Syscall(
-		sysIoUringSetup,
-		uintptr(entries),
-		uintptr(unsafe.Pointer(&params[0])),
-		0,
-	)
-	runtime.KeepAlive(params)
-	if errno != 0 {
-		return 0, fmt.Errorf("io_uring_setup: %w", errno)
-	}
-	return int(fd), nil
-}
-
 // crash simulates a workload that fails with a non-zero exit code.
 // Used to verify the test harness handles workload failures gracefully.
 func crash() error {