Re: [PATCH v1] perf tests: Fix hwmon parsing with PMU name test

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Thu, Nov 21, 2024 at 02:04:45PM -0300, Arnaldo Carvalho de Melo wrote:
> On Wed, Nov 20, 2024 at 04:09:55PM -0800, Ian Rogers wrote:
> > Incorrectly the hwmon with PMU name test didn't pass "true". Fix and
> > address issue with hwmon_pmu__config_terms needing to load events - a
> > load bearing assert fired. Also fix missing list deletion when putting
> > the hwmon test PMU and lower some debug warnings to make the hwmon PMU
> > less spammy in verbose mode.
 
> After applying this, with this series of patches on a Fedora 40 system,
> I get output from -v where before I needed, IIRC, to use -vv:
> 
> f8244bb9bfa66f79 (HEAD -> perf-tools-next, x1/perf-tools-next) perf tests: Fix hwmon parsing with PMU name test
> 9ae6c7a4bd02acbd perf hwmon_pmu: Ensure hwmon key union is zeroed before use
> 3e37de098af38179 perf tests hwmon_pmu: Remove double evlist__delete()
> 0565017a0ac824c2 perf test: Correct hwmon test PMU detection
> 85c60a01b85ee956 (perf-tools-next/tmp.perf-tools-next, perf-tools-next/perf-tools-next) perf: Remove unused del_perf_probe_events()
> ⬢ [acme@toolbox perf-tools-next]$

<SNIP>

> root@number:~# perf test -v 11
>  11: Hwmon PMU                                                       :
>  11.1: Basic parsing test                                            : Ok
> --- start ---
> test child forked, pid 1823259
> Testing 'temp_test_hwmon_event1'
> Using CPUID GenuineIntel-6-B7-1
> FAILED tests/hwmon_pmu.c:159 failed to parse event 'temp_test_hwmon_event1', err 1
> event syntax error: 'temp_test_hwmon_event1'
>                      \___ Bad event name
> 
> Unable to find event on a PMU of 'temp_test_hwmon_event1'

In gdb it fails on the first call to do_test() from the first test__hwmon_pmu()

Starting program: /root/bin/perf test -F -vv 11
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
--- start ---
---- end ----
 11.1: Basic parsing test                                            : Ok
--- start ---

Breakpoint 1, test__hwmon_pmu (with_pmu=false) at tests/hwmon_pmu.c:203
203	{
(gdb) n
205		struct perf_pmu *pmu = test_pmu_get(dir, sizeof(dir));
(gdb) n
206		int ret = TEST_OK;
(gdb) p pmu
$2 = (struct perf_pmu *) 0xf50450
(gdb) p *pmu
$3 = {name = 0xf50ac0 "hwmon_a_test_hwmon_pmu", alias_name = 0xf50aa0 "hwmon1234", id = 0x0, type = 4294902994, selectable = false, is_core = false, is_uncore = false, auxtrace = false, 
  formats_checked = false, config_masks_present = false, config_masks_computed = false, max_precise = 0, perf_event_attr_init_default = 0x0, cpus = 0xf4fbf0, format = {next = 0xf50488, 
    prev = 0xf50488}, aliases = {next = 0xf50498, prev = 0xf50498}, events_table = 0x0, sysfs_aliases = 0, cpu_json_aliases = 0, sys_json_aliases = 0, sysfs_aliases_loaded = false, 
  cpu_aliases_added = false, caps_initialized = false, nr_caps = 0, caps = {next = 0xf504c8, prev = 0xf504c8}, list = {next = 0xedc090 <other_pmus>, prev = 0xedc090 <other_pmus>}, 
  config_masks = {0, 0, 0, 0}, missing_features = {exclude_guest = false, checked = false}, mem_events = 0x0}
(gdb) s
208		if (!pmu)
(gdb) s
211		for (size_t i = 0; i < ARRAY_SIZE(test_events); i++) {
(gdb) s
212			ret = do_test(i, with_pmu, /*with_alias=*/false);
(gdb) s
do_test (i=0, with_pmu=false, with_alias=false) at tests/hwmon_pmu.c:136
136	{
(gdb) n
137		const char *test_event = with_alias ? test_events[i].alias : test_events[i].name;
(gdb) n
138		struct evlist *evlist = evlist__new();
(gdb) n
143		bool found = false;
(gdb) n
145		if (!evlist) {
(gdb) n
150		if (with_pmu)
(gdb) n
153			strlcpy(str, test_event, sizeof(str));
(gdb) n
155		pr_debug("Testing '%s'\n", str);
(gdb) p str
$4 = "temp_test_hwmon_event1\000\000\004\000\000\000\000\000\000\000\274\204z\000\000\000\000\000΄z\000\000\000\000\000\021\000\000\000\000\000\000\000 \305\377\377\377\177\000\000߄z\000\000\000\000\000\353\204z\000\000\000\000\000\376\204z\000\000\000\000\000\n\205z\000\000\000\000\000\021\205z\000\000\000\000\000\035\205z\000\000\000\000\0000\205z\000\000\000\000\000<\205z\000\000\000\000"
(gdb) n
Testing 'temp_test_hwmon_event1'
156		parse_events_error__init(&err);
(gdb) n
157		ret = parse_events(evlist, str, &err);
(gdb) n
Using CPUID GenuineIntel-6-B7-1
158		if (ret) {
(gdb) p ret
$5 = 1
(gdb) n
159			pr_debug("FAILED %s:%d failed to parse event '%s', err %d\n",
(gdb)