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[PATCH] perf/x86/intel: fix integer overflow when shifting 32 places

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  [PATCH] perf/x86/intel: fix integer overflow when shifting 32 places Colin King <colin.king@canonical.com> - 2017-01-11 12:50 +0100
    [tip:perf/urgent] perf/x86/intel: Use ULL constant to prevent  undefined shift behaviour tip-bot for Colin King <tipbot@zytor.com> - 2017-01-11 16:50 +0100

#1556416 — [PATCH] perf/x86/intel: fix integer overflow when shifting 32 places

From: Colin Ian King <colin.king@canonical.com>

When x86_pmu.num_counters is set to INTEL_PMC_MAX_GENERIC we end up
with the 32 bit integer constant 1 being shifted 32 places leading to
undefined behaviour.  Fix this by shifting 1ULL instead of 1.

Fixes CoverityScan CID#1192105 ("Bad bit shift operation")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 arch/x86/events/intel/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 8613826..d611cab 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3987,7 +3987,7 @@ __init int intel_pmu_init(void)
 		     x86_pmu.num_counters, INTEL_PMC_MAX_GENERIC);
 		x86_pmu.num_counters = INTEL_PMC_MAX_GENERIC;
 	}
-	x86_pmu.intel_ctrl = (1 << x86_pmu.num_counters) - 1;
+	x86_pmu.intel_ctrl = (1ULL << x86_pmu.num_counters) - 1;
 
 	if (x86_pmu.num_counters_fixed > INTEL_PMC_MAX_FIXED) {
 		WARN(1, KERN_ERR "hw perf events fixed %d > max(%d), clipping!",
-- 
2.10.2

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#1556647 — [tip:perf/urgent] perf/x86/intel: Use ULL constant to prevent undefined shift behaviour

Commit-ID:  ad5013d5699d30ded0cdbbc68b93b2aa28222c6e
Gitweb:     http://git.kernel.org/tip/ad5013d5699d30ded0cdbbc68b93b2aa28222c6e
Author:     Colin King <colin.king@canonical.com>
AuthorDate: Wed, 11 Jan 2017 11:43:10 +0000
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 11 Jan 2017 16:43:30 +0100

perf/x86/intel: Use ULL constant to prevent undefined shift behaviour

When x86_pmu.num_counters is 32 the shift of the integer constant 1 is
exceeding 32bit and therefor undefined behaviour.

Fix this by shifting 1ULL instead of 1.

Reported-by: CoverityScan CID#1192105 ("Bad bit shift operation")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: http://lkml.kernel.org/r/20170111114310.17928-1-colin.king@canonical.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/events/intel/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 8613826..d611cab 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3987,7 +3987,7 @@ __init int intel_pmu_init(void)
 		     x86_pmu.num_counters, INTEL_PMC_MAX_GENERIC);
 		x86_pmu.num_counters = INTEL_PMC_MAX_GENERIC;
 	}
-	x86_pmu.intel_ctrl = (1 << x86_pmu.num_counters) - 1;
+	x86_pmu.intel_ctrl = (1ULL << x86_pmu.num_counters) - 1;
 
 	if (x86_pmu.num_counters_fixed > INTEL_PMC_MAX_FIXED) {
 		WARN(1, KERN_ERR "hw perf events fixed %d > max(%d), clipping!",

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