RE: BT GATT DM Workqueue Stack Size

Einar Thorsrud — Thu, 19 Mar 2026 14:34:38 GMT

Hi,

I cannot see that there is a good reason for not having the GATT DM workqueue size user configurable. I have reported this internally. For now, you can make it configurable by doing a small change in nrf/subsys/bluetooth/Kconfig.discovery so that BT_GATT_DM_WORKQ_STACK_SIZE looks like this:

config BT_GATT_DM_WORKQ_STACK_SIZE
	int  "GATT Discovery Manager workqueue stack size."
	default 1300 if BT_GATT_CACHING
	default 1024

Edit: to avoid modifying SDK code you can also override by using an application specific Kconfig file containing the following (adjust as needed):

config BT_GATT_DM_WORKQ_STACK_SIZE
	default 2048

source "Kconfig.zephyr"

RE: BT GATT DM Workqueue Stack Size

variant — Wed, 18 Mar 2026 20:38:18 GMT

An additional question: Why was CONFIG_BT_GATT_DM_WORKQ_STACK_SIZE deliberately made a hidden option?

The comment for that CONFIG says "Hidden option for workqueue stack size. Should be derived from system requirements."
The problem is that that workqueue includes callbacks to our application code, which to me is part of the system. Even though we want to limit the amount of work done in that context as part of the callback, why do we have to limit our stack use too, as constrained by the hidden CONFIG_BT_GATT_DM_WORKQ_STACK_SIZE?