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Fix cpumeter segfault #2025

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Fix cpumeter segfault #2025

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143147e
Fix segfault when vCPUs are hot-added: resize AllCPUsMeter data->mete…
Jun 17, 2026
6f86c5f
Housekeeping: Make count, start, ncol unsigned, removes lots of casting
Jun 17, 2026
73cf23c
Address review feedback from @Explorer09
Jun 24, 2026
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51 changes: 37 additions & 14 deletions CPUMeter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -252,27 +252,37 @@ static void AllCPUsMeter_getRange(const Meter* this, int* start, int* count) {
}
}

static void AllCPUsMeter_updateValues(Meter* this) {
CPUMeterData* data = this->meterData;
Meter** meters = data->meters;
int start, count;
AllCPUsMeter_getRange(this, &start, &count);
for (int i = 0; i < count; i++)
Meter_updateValues(meters[i]);
}

static void CPUMeterCommonInit(Meter* this) {
int start, count;
AllCPUsMeter_getRange(this, &start, &count);

CPUMeterData* data = this->meterData;
if (!data) {
data = xCalloc(1, sizeof(CPUMeterData));
data->cpus = this->host->existingCPUs;
data->meters = count ? xCalloc(count, sizeof(Meter*)) : NULL;
data->cpus = 0; /* no meters allocated yet */
data->meters = NULL;
this->meterData = data;
}

assert(count >= 0);
unsigned int prevCount = data->cpus;
if ((unsigned int)count != prevCount) {
/* free meters for CPUs that are no longer in range */
for (unsigned int i = (unsigned int)count; i < prevCount; i++)
Meter_delete((Object*)data->meters[i]);

if (count > 0) {
data->meters = xReallocArray(data->meters, (unsigned int)count, sizeof(Meter*));
/* zero-fill newly added entries */
if ((unsigned int)count > prevCount)
memset(data->meters + prevCount, 0, ((unsigned int)count - prevCount) * sizeof(Meter*));

@Explorer09 Explorer09 Jun 21, 2026

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Consider using xReallocArrayZero.

} else {
free(data->meters);
data->meters = NULL;
}
data->cpus = (unsigned int)count;
}

Meter** meters = data->meters;
for (int i = 0; i < count; i++) {
if (!meters[i])
Expand All @@ -282,7 +292,22 @@ static void CPUMeterCommonInit(Meter* this) {
}
}

static void AllCPUsMeter_updateValues(Meter* this) {
CPUMeterData* data = this->meterData;
int start, count;
AllCPUsMeter_getRange(this, &start, &count);
/* Reinit if the number of CPUs changed (e.g. hot-plug) */
if ((unsigned int)count != data->cpus)
CPUMeterCommonInit(this);
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data = this->meterData;
Meter** meters = data->meters;
for (int i = 0; i < count; i++)
Meter_updateValues(meters[i]);
}

static void CPUMeterCommonUpdateMode(Meter* this, MeterModeId mode, int ncol) {
/* Reinit first in case the CPU count changed since last init */
CPUMeterCommonInit(this);
CPUMeterData* data = this->meterData;
Meter** meters = data->meters;
this->mode = mode;
Expand All @@ -303,9 +328,7 @@ static void CPUMeterCommonUpdateMode(Meter* this, MeterModeId mode, int ncol) {
static void AllCPUsMeter_done(Meter* this) {
CPUMeterData* data = this->meterData;
Meter** meters = data->meters;
int start, count;
AllCPUsMeter_getRange(this, &start, &count);
for (int i = 0; i < count; i++)
for (unsigned int i = 0; i < data->cpus; i++)
Meter_delete((Object*)meters[i]);
free(data->meters);
free(data);
Expand Down