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91 lines
3.3 KiB
Diff
91 lines
3.3 KiB
Diff
From d75be03af111fb5a31eba82f665242e6d8b07008 Mon Sep 17 00:00:00 2001
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From: Arun KS <arunks@codeaurora.org>
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Date: Wed, 11 May 2016 10:11:36 +0530
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Subject: msm: perf: Do not allocate new hw_event if event is 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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Change-Id: Ia3360be027dfe87ac753191ffe7e0bc947e72455
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Signed-off-by: Arun KS <arunks@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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arch/arm/mach-msm/perf_event_msm_l2.c | 4 +++-
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kernel/events/core.c | 7 -------
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4 files changed, 5 insertions(+), 8 deletions(-)
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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 1541a80..a1264ac 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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@@ -308,6 +308,7 @@ 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 d816794..57f82d0 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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@@ -463,6 +463,7 @@ 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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diff --git a/arch/arm/mach-msm/perf_event_msm_l2.c b/arch/arm/mach-msm/perf_event_msm_l2.c
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index f78487a..93695e2 100644
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--- a/arch/arm/mach-msm/perf_event_msm_l2.c
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+++ b/arch/arm/mach-msm/perf_event_msm_l2.c
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@@ -836,8 +836,10 @@ static int msm_l2_test_set_ev_constraint(struct perf_event *event)
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* This sets the event OFF on all but one
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* CPU.
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*/
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- if (!(event->cpu < 0))
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+ if (!(event->cpu < 0)) {
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event->state = PERF_EVENT_STATE_OFF;
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+ err = -EPERM;
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+ }
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}
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out:
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diff --git a/kernel/events/core.c b/kernel/events/core.c
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index 33ad70a..7ebe09a 100644
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--- a/kernel/events/core.c
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+++ b/kernel/events/core.c
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@@ -3030,13 +3030,6 @@ static void put_event(struct perf_event *event)
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if (!atomic_long_dec_and_test(&event->refcount))
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return;
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- /*
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- * Event can be in state OFF because of a constraint check.
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- * Change to ACTIVE so that it gets cleaned up correctly.
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- */
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- if ((event->state == PERF_EVENT_STATE_OFF) &&
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- event->attr.constraint_duplicate)
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- event->state = PERF_EVENT_STATE_ACTIVE;
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rcu_read_lock();
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owner = ACCESS_ONCE(event->owner);
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--
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cgit v1.1
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