[009/151] perf_event: Initialize data.period in perf_swevent_hrtimer()

Greg KH
2009-12-17T04:52:44Z

From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>

commit 59d069eb5ae9b033ed1c124c92e1532c4a958991 upstream.

In current code in perf_swevent_hrtimer(), data.period is not
initialized, The result is obvious wrong:

# ./perf record -f -e cpu-clock make
# ./perf report
# Samples: 1740
#
# Overhead Command ......
# ........ ........ ..........................................
#
1025422183050275328.00% sh libc-2.9.90.so ...
1025422183050275328.00% perl libperl.so ...
1025422168240043264.00% perl [kernel] ...
1025422030011210752.00% perl [kernel] ...

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B14E220.2050107@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
kernel/perf_event.c | 1 +
1 file changed, 1 insertion(+)

--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3949,6 +3949,7 @@ static enum hrtimer_restart perf_swevent
event->pmu->read(event);

data.addr = 0;
+ data.period = event->hw.last_period;
regs = get_irq_regs();
/*
* In case we exclude kernel IPs or are somehow not in interrupt