BLE library has a memory leak. #4753
Comments
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Your memory leak is because you create a new BLEClient instance every time |
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BLEClient should be deleted by library after disconnecting, but i agree, try to use NimBLE, more pros than cons. |
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Thanks for the reply. I fixed it to delete the client at the end of connectToServer, but now the device crashes. bool connectToServer()
{
BLEClient *pClient = BLEDevice::createClient();
if (!pClient->connect(myDevice))
{
Serial.print("Failed to find our service UUID: ");
Serial.println(serviceUUID.toString().c_str());
return false;
}
BLERemoteService *pRemoteService = pClient->getService(serviceUUID);
if (pRemoteService == nullptr)
{
Serial.print("Failed to find our service UUID: ");
Serial.println(serviceUUID.toString().c_str());
pClient->disconnect();
return false;
}
BLERemoteCharacteristic *pRemoteCharacteristic = pRemoteService->getCharacteristic(charUUID);
if (pRemoteCharacteristic == nullptr)
{
Serial.print("Failed to find our characteristic UUID: ");
Serial.println(charUUID.toString().c_str());
pClient->disconnect();
return false;
}
if (pRemoteCharacteristic->canRead())
{
std::string value = pRemoteCharacteristic->readValue();
Serial.print("The characteristic value was: ");
Serial.println(value.c_str());
}
pClient->disconnect();
delete pClient; // added
return true;
}Here is the log. I'll refer to NimBLE. |
Oops, I forgot about this, sorry for bad info. Curious about the memory leak then. |
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I've tried different approach. Changed the client to a global variable and delete the previous instance before create a new instance. static BLEClient *pClient;
bool connectToServer()
{
if (pClient != nullptr)
{
delete pClient;
}
pClient = BLEDevice::createClient();
if (!pClient->connect(myDevice))
{
Serial.print("Failed to find our service UUID: ");
Serial.println(serviceUUID.toString().c_str());
return false;
}
BLERemoteService *pRemoteService = pClient->getService(serviceUUID);
if (pRemoteService == nullptr)
{
Serial.print("Failed to find our service UUID: ");
Serial.println(serviceUUID.toString().c_str());
pClient->disconnect();
return false;
}
BLERemoteCharacteristic *pRemoteCharacteristic = pRemoteService->getCharacteristic(charUUID);
if (pRemoteCharacteristic == nullptr)
{
Serial.print("Failed to find our characteristic UUID: ");
Serial.println(charUUID.toString().c_str());
pClient->disconnect();
return false;
}
if (pRemoteCharacteristic->canRead())
{
std::string value = pRemoteCharacteristic->readValue();
Serial.print("The characteristic value was: ");
Serial.println(value.c_str());
}
pClient->disconnect();
return true;
}I used the serial plotter in the Arduino IDE to plot the heap size, and it looks like this For Your Information |
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Good approach, definitely looks like there's some bugs to stomp. |
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The crashes that sometimes occurred with the above approach seem to have gone away after the following modification to the BLEClient destructor. BLEClient::~BLEClient() {
// We may have allocated service references associated with this client. Before we are finished
// with the client, we must release resources.
for (auto &myPair : m_servicesMap) {
delete myPair.second;
}
m_servicesMap.clear();
m_servicesMapByInstID.clear(); // added
} // ~BLEClientBut, the free space in the heap memory is still decreasing. |
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I found the cause. BLERemoteCharacteristic::~BLERemoteCharacteristic() {
removeDescriptors(); // Release resources for any descriptor information we may have allocated.
if (m_rawData != nullptr)
{
free(m_rawData);
}
} // ~BLERemoteCharacteristicThe graph of free heap memory space after the change is as follows. |
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just a side note: it is perfectly legal to call free() or delete() on a nullptr, so any check that only guards one of the two calls is unnecessary at best or confusing otherwise. |
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Thanks for your advice. |
me-no-dev
pushed a commit
that referenced
this issue
Feb 15, 2021
* Fixed crash on delete after disconnect * Fixed memory leak when getting characteristics * Removed guard Co-authored-by: ushiboy <[email protected]>
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Hardware:
Board: ESP32 Dev Module
Core Installation version: 1.0.5-rc6
IDE name: Arduino IDE 1.8.13
Flash Frequency: 80Mhz
PSRAM enabled: no
Upload Speed: 921600
Computer OS: Ubuntu 18.04.5 LTS
Description:
I ran the following code as a central device for BLE.
Then the free space in the heap memory gradually decreased and finally the device hung.
I used the BLE_server sample sketch for the peripherals.
Sketch:
Debug Messages:
The text was updated successfully, but these errors were encountered: