net: mgmt: Use proper coop thread priority value

If user sets CONFIG_NUM_PREEMPT_PRIORITIES=0, then the priority
of the net_mgmt thread will be -1 which is the same as idle thread.
This will trigger assert in kernel as then the minimum coop priority
is -2 in this case. Remove the net_mgmt thread priority setting from
Kconfig file as it is low value and set the coop thread priority
the same way as other network threads are doing it.

Fixes #32375

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

subsys/net/ip/Kconfig.mgmt

@@ -27,14 +27,6 @@ config NET_MGMT_EVENT_STACK_SIZE
 	  Set the internal stack size for NM to run registered callbacks
 	  on events.
 
-config NET_MGMT_EVENT_THREAD_PRIO
-	int "Inner thread priority (use with care)"
-	default -1 if NET_TC_THREAD_COOPERATIVE
-	default 7
-	help
-	  Set the network management event core's inner thread priority.
-	  Do not change this unless you know what you are doing.
-
 config NET_MGMT_EVENT_QUEUE_SIZE
 	int "Size of event queue"
 	default 16 if NET_MGMT_EVENT_MONITOR

subsys/net/ip/net_mgmt.c

@@ -386,10 +386,17 @@ void net_mgmt_event_init(void)
 	(void)memset(events, 0, CONFIG_NET_MGMT_EVENT_QUEUE_SIZE *
 			sizeof(struct mgmt_event_entry));
 
+#if IS_ENABLED(CONFIG_NET_TC_THREAD_COOPERATIVE)
+/* Lowest priority cooperative thread */
+#define THREAD_PRIORITY K_PRIO_COOP(CONFIG_NUM_COOP_PRIORITIES - 1)
+#else
+#define THREAD_PRIORITY K_PRIO_PREEMPT(CONFIG_NUM_PREEMPT_PRIORITIES - 1)
+#endif
+
 	k_thread_create(&mgmt_thread_data, mgmt_stack,
 			K_KERNEL_STACK_SIZEOF(mgmt_stack),
 			(k_thread_entry_t)mgmt_thread, NULL, NULL, NULL,
-			CONFIG_NET_MGMT_EVENT_THREAD_PRIO, 0, K_NO_WAIT);
+			THREAD_PRIORITY, 0, K_NO_WAIT);
 	k_thread_name_set(&mgmt_thread_data, "net_mgmt");
 
 	NET_DBG("Net MGMT initialized: queue of %u entries, stack size of %u",

tests/net/all/prj.conf

@@ -207,7 +207,6 @@ CONFIG_NET_CONFIG_NEED_IPV6=y
 CONFIG_NET_MGMT=y
 CONFIG_NET_MGMT_EVENT=y
 CONFIG_NET_MGMT_EVENT_STACK_SIZE=800
-CONFIG_NET_MGMT_EVENT_THREAD_PRIO=66
 CONFIG_NET_MGMT_EVENT_QUEUE_SIZE=2
 CONFIG_NET_MGMT_EVENT_LOG_LEVEL_DBG=y
 CONFIG_NET_DEBUG_MGMT_EVENT_STACK=y

tests/net/lib/dns_addremove/prj.conf

@@ -9,7 +9,6 @@ CONFIG_DNS_NUM_CONCUR_QUERIES=1
 CONFIG_NET_LOG=y
 CONFIG_NET_MGMT=y
 CONFIG_NET_MGMT_EVENT=y
-CONFIG_NET_MGMT_EVENT_THREAD_PRIO=7
 CONFIG_NET_MGMT_EVENT_QUEUE_SIZE=2
 CONFIG_NET_IPV4=y
 CONFIG_NET_IPV6=y