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ARM: perf: initialise used_mask for fake PMU during validation

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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>
This commit is contained in:
Will Deacon 2011-11-17 15:05:14 +00:00
parent 14e25c5eeb
commit bce34d1442
1 changed files with 7 additions and 1 deletions
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8
arch/arm/kernel/perf_event.c
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@ -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;