Commit bce34d14 authored Nov 17, 2011 by Will Deacon

ARM: perf: initialise used_mask for fake PMU during validation



When validating an event group, we call pmu->get_event_idx for each
group member in order to check that the group can be scheduled as a
unit on an empty PMU.

As a result of 3fc2c830 ("ARM: perf: remove event limit from
pmu_hw_events"), the used_mask member of struct cpu_hw_events must be
setup explicitly, something which we don't do for the fake cpu_hw_events
used for validation.

This patch sets up an empty used_mask for the fake validation
cpu_hw_events, preventing NULL deferences when trying to get the event
index.

Reported-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

parent 14e25c5e

arch/arm/kernel/perf_event.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -343,8 +343,14 @@ validate_group(struct perf_event *event)
		{
		struct perf_event sibling, leader = event->group_leader;
		struct pmu_hw_events fake_pmu;
		DECLARE_BITMAP(fake_used_mask, ARMPMU_MAX_HWEVENTS);

		memset(&fake_pmu, 0, sizeof(fake_pmu));
		/*
		* Initialise the fake PMU. We only need to populate the
		* used_mask for the purposes of validation.
		*/
		memset(fake_used_mask, 0, sizeof(fake_used_mask));
		fake_pmu.used_mask = fake_used_mask;

		if (!validate_event(&fake_pmu, leader))
		return -ENOSPC;