kernel/trace/trace_event_perf.c | 6 ++++++ 1 file changed, 6 insertions(+)
When a tracepoint event is created with attr.freq = 1,
'hwc->period_left' is not initialized correctly. As a result,
in the perf_swevent_overflow() function, when the first time the event occurs,
it calculates the event overflow and the perf_swevent_set_period() returns 3,
this leads to the event are recorded for three duplicate times.
Step to reproduce:
1. Enable the tracepoint event & starting tracing
$ echo 1 > /sys/kernel/tracing/events/module/module_free
$ echo 1 > /sys/kernel/tracing/tracing_on
2. Record with perf
$ perf record -a --strict-freq -F 1 -e "module:module_free"
3. Trigger module_free event.
$ modprobe -i sunrpc
$ modprobe -r sunrpc
Result:
- Trace pipe result:
$ cat trace_pipe
modprobe-174509 [003] ..... 6504.868896: module_free: sunrpc
- perf sample:
modprobe 174509 [003] 6504.868980: module:module_free: sunrpc
modprobe 174509 [003] 6504.868980: module:module_free: sunrpc
modprobe 174509 [003] 6504.868980: module:module_free: sunrpc
By setting period_left via perf_swevent_set_period() as other sw_event did,
This problem could be solved.
After patch:
- Trace pipe result:
$ cat trace_pipe
modprobe 1153096 [068] 613468.867774: module:module_free: xfs
- perf sample
modprobe 1153096 [068] 613468.867794: module:module_free: xfs
Fixes: bd2b5b12849a ("perf_counter: More aggressive frequency adjustment")
Signed-off-by: Levi Yun <yeoreum.yun@arm.com>
---
kernel/trace/trace_event_perf.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 05e791241812..9050c631fe06 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -352,10 +352,16 @@ void perf_uprobe_destroy(struct perf_event *p_event)
int perf_trace_add(struct perf_event *p_event, int flags)
{
struct trace_event_call *tp_event = p_event->tp_event;
+ struct hw_perf_event *hwc = &p_event->hw;
if (!(flags & PERF_EF_START))
p_event->hw.state = PERF_HES_STOPPED;
+ if (is_sampling_event(event)) {
+ hwc->last_period = hwc->sample_period;
+ perf_swevent_set_period(p_event);
+ }
+
/*
* If TRACE_REG_PERF_ADD returns false; no custom action was performed
* and we need to take the default action of enqueueing our event on
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}Hi Levi,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.11-rc7 next-20240912]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Levi-Yun/trace-trace_event_perf-remove-duplicate-samples-on-the-first-tracepoint-event/20240911-202917
base: linus/master
patch link: https://lore.kernel.org/r/20240911122747.4168556-1-yeoreum.yun%40arm.com
patch subject: [PATCH] trace/trace_event_perf: remove duplicate samples on the first tracepoint event
config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20240913/202409130445.H7LIIGpd-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240913/202409130445.H7LIIGpd-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409130445.H7LIIGpd-lkp@intel.com/
All errors (new ones prefixed by >>):
>> kernel/trace/trace_event_perf.c:360:24: error: use of undeclared identifier 'event'
360 | if (is_sampling_event(event)) {
| ^
1 error generated.
vim +/event +360 kernel/trace/trace_event_perf.c
351
352 int perf_trace_add(struct perf_event *p_event, int flags)
353 {
354 struct trace_event_call *tp_event = p_event->tp_event;
355 struct hw_perf_event *hwc = &p_event->hw;
356
357 if (!(flags & PERF_EF_START))
358 p_event->hw.state = PERF_HES_STOPPED;
359
> 360 if (is_sampling_event(event)) {
361 hwc->last_period = hwc->sample_period;
362 perf_swevent_set_period(p_event);
363 }
364
365 /*
366 * If TRACE_REG_PERF_ADD returns false; no custom action was performed
367 * and we need to take the default action of enqueueing our event on
368 * the right per-cpu hlist.
369 */
370 if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event)) {
371 struct hlist_head __percpu *pcpu_list;
372 struct hlist_head *list;
373
374 pcpu_list = tp_event->perf_events;
375 if (WARN_ON_ONCE(!pcpu_list))
376 return -EINVAL;
377
378 list = this_cpu_ptr(pcpu_list);
379 hlist_add_head_rcu(&p_event->hlist_entry, list);
380 }
381
382 return 0;
383 }
384
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Levi,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.11-rc7 next-20240912]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Levi-Yun/trace-trace_event_perf-remove-duplicate-samples-on-the-first-tracepoint-event/20240911-202917
base: linus/master
patch link: https://lore.kernel.org/r/20240911122747.4168556-1-yeoreum.yun%40arm.com
patch subject: [PATCH] trace/trace_event_perf: remove duplicate samples on the first tracepoint event
config: sparc64-defconfig (https://download.01.org/0day-ci/archive/20240912/202409122013.3PMFMv8D-lkp@intel.com/config)
compiler: sparc64-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240912/202409122013.3PMFMv8D-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409122013.3PMFMv8D-lkp@intel.com/
All errors (new ones prefixed by >>):
kernel/trace/trace_event_perf.c: In function 'perf_trace_add':
>> kernel/trace/trace_event_perf.c:360:31: error: 'event' undeclared (first use in this function); did you mean 'p_event'?
360 | if (is_sampling_event(event)) {
| ^~~~~
| p_event
kernel/trace/trace_event_perf.c:360:31: note: each undeclared identifier is reported only once for each function it appears in
vim +360 kernel/trace/trace_event_perf.c
351
352 int perf_trace_add(struct perf_event *p_event, int flags)
353 {
354 struct trace_event_call *tp_event = p_event->tp_event;
355 struct hw_perf_event *hwc = &p_event->hw;
356
357 if (!(flags & PERF_EF_START))
358 p_event->hw.state = PERF_HES_STOPPED;
359
> 360 if (is_sampling_event(event)) {
361 hwc->last_period = hwc->sample_period;
362 perf_swevent_set_period(p_event);
363 }
364
365 /*
366 * If TRACE_REG_PERF_ADD returns false; no custom action was performed
367 * and we need to take the default action of enqueueing our event on
368 * the right per-cpu hlist.
369 */
370 if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event)) {
371 struct hlist_head __percpu *pcpu_list;
372 struct hlist_head *list;
373
374 pcpu_list = tp_event->perf_events;
375 if (WARN_ON_ONCE(!pcpu_list))
376 return -EINVAL;
377
378 list = this_cpu_ptr(pcpu_list);
379 hlist_add_head_rcu(&p_event->hlist_entry, list);
380 }
381
382 return 0;
383 }
384
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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