From: Adam Borowski <kilobyte@...>

commit 0a25556f84d5f79e68e9502bb1f32a43377ab2bf upstream.

The entry for PERF_COUNT_HW_REF_CPU_CYCLES is not used on AMD, but is
referenced by filter_events() which expects undefined events to have a
value of 0.

Found via KASAN:

UBSAN: Undefined behaviour in arch/x86/events/amd/core.c:132:30
index 9 is out of range for type 'u64 [9]'
UBSAN: Undefined behaviour in arch/x86/events/amd/core.c:132:9
load of address ffffffff81c021c8 with insufficient space for an object of type 'const u64'

Signed-off-by: Adam Borowski <kilobyte@...>
Cc: Alexander Shishkin <alexander.shishkin@...>
Cc: Arnaldo Carvalho de Melo <acme@...>
Cc: Borislav Petkov <bp@...>
Cc: Jiri Olsa <jolsa@...>
Cc: Mike Galbraith <efault@...>
Cc: Peter Zijlstra <peterz@...>
Cc: Stephane Eranian <eranian@...>
Cc: Thomas Gleixner <tglx@...>
Cc: Vince Weaver <vincent.weaver@...>
Link: http://lkml.kernel.org/r/1461749731-30979-1-git-send-email-kilobyte@angband.pl
Signed-off-by: Ingo Molnar <mingo@...>
[bwh: Backported to 4.4: adjust filename]

Signed-off-by: Ben Hutchings <ben.hutchings@...>
---
arch/x86/kernel/cpu/perf_event_amd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c
index 1cee5d2d7ece..e671f3c2397e 100644
--- a/arch/x86/kernel/cpu/perf_event_amd.c
+++ b/arch/x86/kernel/cpu/perf_event_amd.c
@@ -115,7 +115,7 @@ static __initconst const u64 amd_hw_cache_event_ids
/*
* AMD Performance Monitor K7 and later.
*/
-static const u64 amd_perfmon_event_map[] =
+static const u64 amd_perfmon_event_map[PERF_COUNT_HW_MAX] =
{
[PERF_COUNT_HW_CPU_CYCLES] = 0x0076,
[PERF_COUNT_HW_INSTRUCTIONS] = 0x00c0,
--
2.10.2



--
Ben Hutchings
Software Developer, Codethink Ltd.