#!/bin/bash# Test that perf report includes file offsets and event type names in diagnostic messages.# SPDX-License-Identifier: GPL-2.0## The file_offset diagnostic series adds "at offset 0x...: TYPE (N)"# to all skip/stop/error messages.  This test corrupts an event's size# field in a perf.data file, then verifies the resulting warning# includes the file offset and event type. err=0 cleanup() {	[ -n "${perfdata}" ] && rm -f "${perfdata}" "${perfdata}.old"	rm -f "${corrupted}" "${stderrfile}"	trap - EXIT TERM INT}trap 'cleanup; exit 1' TERM INTtrap cleanup EXIT perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX) || exit 2corrupted=$(mktemp /tmp/__perf_test.perf.data.XXXXX) || exit 2stderrfile=$(mktemp /tmp/__perf_test.perf.data.XXXXX) || exit 2 if ! perf record -o "${perfdata}" -- perf test -w noploop 2>/dev/null; then	echo "Skip: perf record failed"	cleanup	exit 2fi # Find the file offset of the first MMAP2 event via perf report -D.# Format: "timestamp 0xOFFSET [0xSIZE]: PERF_RECORD_MMAP2 ..."mmap2_line=$(perf report -D -i "${perfdata}" 2>/dev/null | grep "PERF_RECORD_MMAP2" | head -1)if [ -z "${mmap2_line}" ]; then	echo "Skip: no MMAP2 events found in perf.data"	cleanup	exit 2fi mmap2_offset=$(echo "${mmap2_line}" | awk '{print $2}')mmap2_offset_dec=$((mmap2_offset)) # Copy the file and corrupt the MMAP2 event's size field.# perf_event_header layout: type(u32) misc(u16) size(u16)# Set size to 16 — below the MMAP2 minimum, which triggers# the "event size too small" warning.## perf.data uses native byte order, so write the u16 in the# host's endianness to work on both LE and BE architectures.cp "${perfdata}" "${corrupted}"if printf '\x01\x02' | od -A n -t x2 | grep -q "0201"; then	# Little-endian	printf '\x10\x00'else	# Big-endian	printf '\x00\x10'fi | dd of="${corrupted}" bs=1 seek=$((mmap2_offset_dec + 6)) conv=notrunc 2>/dev/null perf report -i "${corrupted}" --stdio > /dev/null 2> "${stderrfile}" # Check that warnings include "at offset 0x..."if grep -q "at offset 0x" "${stderrfile}"; then	echo "File offset in diagnostics [Success]"else	echo "File offset in diagnostics [Failed: no 'at offset 0x...' found]"	echo "  stderr was:"	head -5 "${stderrfile}"	err=1fi # Check that the event type name and numeric id appear: "MMAP2 (10)"if grep -q "MMAP2 (10)" "${stderrfile}"; then	echo "Event type name in diagnostics [Success]"else	echo "Event type name in diagnostics [Failed: no 'MMAP2 (10)' found]"	echo "  stderr was:"	head -5 "${stderrfile}"	err=1fi # Check that the reported offset matches the actual corruption pointif grep -q "at offset ${mmap2_offset}:" "${stderrfile}"; then	echo "Correct offset reported [Success]"else	echo "Correct offset reported [Failed: expected offset ${mmap2_offset}]"	echo "  stderr was:"	head -5 "${stderrfile}"	err=1fi cleanupexit ${err}