Qt5 and Qt6 Bluetooth crashes on segmentation fault.

Zmmfly

Hello everyone.

When running with QBluetooth, and call "QLowEnergyService::discoverDetails", it random crash.
There are the trace of my application:

Thread 41 received signal SIGSEGV, Segmentation fault.
[Switching to Thread 58424.0xeffc]
0x00007ffdd6a13b6a in Qt5Bluetooth!?setMaxPendingConnections@QBluetoothServer@@QEAAXH@Z ()
   from S:\X\dist\Qt5Bluetooth.dll
(gdb) bt
#0  0x00007ffdd6a13b6a in Qt5Bluetooth!?setMaxPendingConnections@QBluetoothServer@@QEAAXH@Z ()
   from S:\X\dist\Qt5Bluetooth.dll
#1  0x00007ffdd6a12620 in Qt5Bluetooth!?setMaxPendingConnections@QBluetoothServer@@QEAAXH@Z ()
   from S:\X\dist\Qt5Bluetooth.dll
#2  0x00007ff700eb6404 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Qt version:5.15.2
build with msvc

ChrisW67

@Zmmfly The last line says something is trampling on memory it should not be, or you are mixing library versions, or overwriting a fixed buffer... Run a debug build of your program in your debugger and see where it goes wrong. We cannot do that for you.

Zmmfly

@ChrisW67 I try to debug it, The debugger tell me "Unhandled exception at 0x00007FFDCD113B6A (Qt5Bluetooth.dll) in ble_tester.exe: 0xC0000005: Access violation reading location 0x0000000000000000."

Slot

Zmmfly

I think i found solution, before call "QLowEnergyService::discoverDetails", if "QLowEnergyController" emit error signals, and the error is "RemoteHostClosedError", we cannot do it, it will caused crash. The truly method is giveup the conntion, and wait next connection.

Zmmfly

The similar problem: https://forum.qt.io/topic/119766/unknown-exception-is-not-beeing-caught-in-trycatch-block-bluetooth-low-energy-servicedetailsdiscovery