From: Will Deacon Date: Thu, 17 Nov 2011 15:05:14 +0000 (+0000) Subject: ARM: perf: initialise used_mask for fake PMU during validation X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=bce34d14428d35d9a06ddc10cd46ecef311764c9;p=linux-beck.git 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 Signed-off-by: Will Deacon --- diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 24e2347be6b1..e508066d3d64 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -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;