BT_LW_WQ stack overflows with debug options

RE: BT_LW_WQ stack overflows with debug options

ovrebekk — Tue, 24 Jan 2023 13:16:03 GMT

For a non-debug build you shouldn't have to use the workaround at all.

Any issue with the default configuration should be picked up by our own release testing.

Best regards
Torbjørn

RE: BT_LW_WQ stack overflows with debug options

jtrueb — Mon, 23 Jan 2023 15:39:03 GMT

Hi Torbjørn,

Thanks for the workaround option. I will use that for hacks as it is useful in development.

For a non-debug build, the workaround sounds like a bug to me since nothing associates the intended override with the actual SDK version's Kconfig parameter or value.

I am concerned that the workaround adds a manual item to check with each release change that won't be caught at compile time. In my experience, BT_LONG_WQ_STACK_SIZE will probably be renamed to BT_LW_WQ_STACK_SIZE or something and cause stack overflows again on a later release.

RE: BT_LW_WQ stack overflows with debug options

ovrebekk — Mon, 23 Jan 2023 11:39:47 GMT

Hi again

No news on an update from our side yet, but one of the developers alerted me to a better workaround than having to alter the SDK files.

In order to make the BT_LONG_WQ_STACK_SIZE parameter user configurable you can simply add it to your local Kconfig file (just create a file called Kconfig in the project root folder).

Then you can redefine the parameter with any default value you want:

config BT_LONG_WQ_STACK_SIZE
    int "Long workqueue stack size"
    default 2000
    
source "Kconfig.zephyr"

Best regards
Torbjørn

RE: BT_LW_WQ stack overflows with debug options

ovrebekk — Fri, 20 Jan 2023 11:11:13 GMT

Everything is relative I guess 😉

Part of the issue is that the Bluetooth host is not tested in all possible configurations of the project, so you could end up in situations where the stack sizes are not sufficient if you are using a configuration that is not standard.

I still haven't heard back regarding an update to the issue, but I will let you know when I do.
We probably won't have anything in the short term though, so if disabling debug options is not possible you will probably have to patch this yourself for now.

Best regards
Torbjørn

RE: BT_LW_WQ stack overflows with debug options

jtrueb — Thu, 19 Jan 2023 18:25:06 GMT

I checked https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.1.3/nrf/known_issues.html
It is not a known issue, but I understand your point that it is a known issue.

The proper known issue for this is that the VS Code build configuration with "Enable debug options" or use of alternative optimization settings like CONFIG_NO_OPTIMIZATIONS may cause hard faults due to any stack size usage change from release to release. Faults may be expected behavior for such builds, won't fix. The workaround is to edit the NCS SDK installation manually and assign larger stack sizes as needed.

In the future, zephyr could allow parameterized stack usage to fix this issue but likely will not.

RE: BT_LW_WQ stack overflows with debug options

ovrebekk — Thu, 19 Jan 2023 17:22:14 GMT

This is a known issue, and you can follow the existing discussion here:
https://github.com/zephyrproject-rtos/zephyr/issues/52105

I have asked the team for a status update, and I will get back to you once I know more regarding a fix.

Best regards
Torbjørn