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53 lines
2.2 KiB
Diff
53 lines
2.2 KiB
Diff
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From 84d8c81420aaa7c6cd6f57cb52daccf07b1f7a50 Mon Sep 17 00:00:00 2001
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From: Veena Sambasivan <veenas@codeaurora.org>
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Date: Thu, 19 May 2016 18:47:15 -0700
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Subject: [PATCH] msm: perf: Do not allocate new hw_event if event is
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duplicate.
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During a perf_event_enable, kernel/events/core.c calls pmu->add() which
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is platform implementation(arch/arm/kernel/perf_event.c). Due to the
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duplicate constraints, arch/arm/mach-msm/perf_event_msm_krait_l2.c
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drivers marks the event as OFF but returns TRUE to perf_event.c which
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goes ahead and allocates the hw_event and enables it.
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Since event is marked OFF, kernel events core will try to enable this event
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again during next perf_event_enable. Which results in same event enabled
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on multiple hw_events. But during the perf_release, event struct is freed
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and only one hw_event is released. This results in dereferencing the
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invalid pointer and hence the crash.
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Fix this by returning error in case of constraint event duplicate. Hence
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avoiding the same event programmed on multiple hw event counters.
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bug: 28172137
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Change-Id: Ia3360be027dfe87ac753191ffe7e0bc947e72455
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Signed-off-by: Arun KS <arunks@codeaurora.org>
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Signed-off-by: Veena Sambasivan <veenas@codeaurora.org>
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---
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arch/arm/kernel/perf_event.c | 1 +
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arch/arm/mach-msm/perf_event_msm_krait_l2.c | 1 +
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2 files changed, 2 insertions(+)
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diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
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index 0f288a7c035f9..a0c1e318a7905 100644
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--- a/arch/arm/kernel/perf_event.c
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+++ b/arch/arm/kernel/perf_event.c
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@@ -240,6 +240,7 @@ armpmu_add(struct perf_event *event, int flags)
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pr_err("Event: %llx failed constraint check.\n",
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event->attr.config);
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event->state = PERF_EVENT_STATE_OFF;
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+ err = -EPERM;
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goto out;
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}
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diff --git a/arch/arm/mach-msm/perf_event_msm_krait_l2.c b/arch/arm/mach-msm/perf_event_msm_krait_l2.c
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index 65a5d2f8e1bcd..cc39b719b33fb 100644
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--- a/arch/arm/mach-msm/perf_event_msm_krait_l2.c
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+++ b/arch/arm/mach-msm/perf_event_msm_krait_l2.c
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@@ -468,6 +468,7 @@ static int msm_l2_test_set_ev_constraint(struct perf_event *event)
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if (!(event->cpu < 0)) {
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event->state = PERF_EVENT_STATE_OFF;
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event->attr.constraint_duplicate = 1;
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+ err = -EPERM;
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}
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}
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out:
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