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drivers: soc: qcom: update rimps memlat while saving pmu counters

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During hoplug cpu going down path pmu event handles will be freed.
If the hotplug path and idle path run in parallel there are chances
in idle path that the driver will try to read the PMU counters with
freed pointer resulting in a crash.

Add NULL pointer check before performing PMU reads.

Change-Id: I9b8a4a8dfa63e70e879c3530a878a9c96062872f
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>
This commit is contained in:
Santosh Mardi 2020-09-28 21:21:00 +05:30 • committed by Gerrit - the friendly Code Review server
commit 3da3b760c2
1 changed files with 12 additions and 4 deletions
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16
drivers/soc/qcom/rimps_memlat.c
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@ -620,7 +620,8 @@ static void save_cpugrp_pmu_events(struct memlat_cpu_grp *cpu_grp, u8 cpu)
for (i = 0; i < NUM_COMMON_EVS; i++) {
u8 hw_id = pmu[i].hw_cntr_idx;
if (hw_id == INVALID_PMU_HW_IDX)
if ((hw_id == INVALID_PMU_HW_IDX) ||
!cpus_data->common_evs[i])
continue;
perf_event_read_local(cpus_data->common_evs[i],
&ev_count, NULL, NULL);
@ -639,7 +640,8 @@ static void save_mon_pmu_events(struct memlat_mon *mon, u8 cpu)
for (i = 0; i < NUM_MON_EVS; i++) {
u8 hw_id = pmu[i].hw_cntr_idx;
if (hw_id == INVALID_PMU_HW_IDX)
if (hw_id == INVALID_PMU_HW_IDX ||
!ev_data->mon_evs[i])
continue;
perf_event_read_local(ev_data->mon_evs[i],
&ev_count, NULL, NULL);
@ -658,6 +660,7 @@ static void free_common_evs(struct memlat_cpu_grp *cpu_grp, cpumask_t *mask)
if (!cpus_data->common_evs[i])
continue;
perf_event_release_kernel(cpus_data->common_evs[i]);
cpus_data->common_evs[i] = NULL;
}
}
}
@ -674,6 +677,7 @@ static void free_mon_evs(struct memlat_mon *mon, cpumask_t *mask)
continue;
perf_event_release_kernel(ev_data->mon_evs[i]);
ev_data->mon_evs[i] = NULL;
}
}
}
@ -755,8 +759,12 @@ exit:
static int memlat_event_hotplug_coming_up(unsigned int cpu)
{
per_cpu(cpu_is_hp, cpu) = false;
return memlat_hp_restart_events(cpu, true);
int ret;
ret = memlat_hp_restart_events(cpu, true);
if (!ret)
per_cpu(cpu_is_hp, cpu) = false;
return ret;
}
static int memlat_event_hotplug_going_down(unsigned int cpu)