High load for usteerd after wifi was enabled

[stweil]

I run a Freifunk node which enables wifi from 08:00 until 20:00:

# cat /usr/lib/micron.d/local 
*  8 * * * /sbin/wifi up
* 20 * * * /sbin/wifi down

It looks like since the last wifi activation usteerd causes a permanently high system load. This is the first time where I see this effect. Normally there is only a short load peek when wifi is enabled.

Output from top:

Mem: 43276K used, 14428K free, 940K shrd, 0K buff, 18248K cached
CPU:  94% usr   3% sys   0% nic   0% idle   0% io   0% irq   1% sirq
Load average: 0.30 0.31 0.72 3/56 27860
  PID  PPID USER     STAT   VSZ %VSZ %CPU COMMAND
 3011     1 root     R     2244   4%  71% /sbin/usteerd
[...]

usteerd runs in a loop without making system calls:

(gdb) disas 0x77dd33ef,0x77dd3403
Dump of assembler code from 0x77dd33ef to 0x77dd3403:
=> 0x77dd33ef:	cmp	a0,v0
   0x77dd33f1:	btnez	0x77dd33f7
   0x77dd33f3:	li	v0,0
   0x77dd33f5:	b	0x77dd342f
   0x77dd33f7:	lhu	v1,28(v0)
   0x77dd33f9:	lw	a1,12(sp)
   0x77dd33fb:	xor	v1,a1
   0x77dd33fd:	beqz	v1,0x77dd3403
   0x77dd33ff:	lw	v0,0(v0)
   0x77dd3401:	b	0x77dd33ef
End of assembler dump.

Installed packages:

ffda-gluon-usteer - 1.0.0-1
usteer - 2022-08-18-7d2b17c9-1 - OpenWrt AP roaming assist daemon

[stweil]

The load on the router is still high with usteerd using between 80% and 99% of the CPU.

@blocktrron, do you need more data for debugging of this issue? If not, I'd restart usteerd.

[stweil]

The load is high again since 2023-07-28, see statistics. I'll reboot the node tomorrow unless someone wants more debugging information.

[stweil]

While looking at the statistics for the last 6 months, I think that there is also a memory leak somewhere because there is continuously a small increase of the used RAM.

[stweil]

According to the documentation, usteer requires configured 802.11k and 802.11v on all WiFi AP-nodes. It looks like that configuration is missing in current Freifunk installations although they install and run usteer.