[PATCH] perf/rapl: fix crash in rapl_scale()

From: Stephane Eranian
Date: Thu Jan 22 2015 - 15:38:40 EST



This patch fixes a systematic crash in rapl_scale()
due to an invalid pointer.

The bug was introduced by commit:
commit 89cbc76768c2fa4ed95545bf961f3a14ddfeed21
Author: Christoph Lameter <cl@xxxxxxxxx>
Date: Sun Aug 17 12:30:40 2014 -0500

x86: Replace __get_cpu_var uses


The fix is simple. Just put the parenthesis where it needs
to be, i.e., around rapl_pmu. To my surprise, the compiler
was not complaining about passing an integer instead of a
pointer.

Reported-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
Tested-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
--

diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
index 6e434f8..c4bb8b8 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
@@ -142,7 +142,7 @@ static inline u64 rapl_scale(u64 v)
* or use ldexp(count, -32).
* Watts = Joules/Time delta
*/
- return v << (32 - __this_cpu_read(rapl_pmu->hw_unit));
+ return v << (32 - __this_cpu_read(rapl_pmu)->hw_unit);
}

static u64 rapl_event_update(struct perf_event *event)
--
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