FS#3421 : netifd: tries to claim VAP device before it's created

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Status Unconfirmed
Percent Complete
0%
Task Type Bug Report
Category Base system
Assigned To No-one
Operating System All
Severity Medium
Priority Very Low
Reported Version Trunk
Due in Version Undecided
Due Date Undecided
Private

Attached to Project: OpenWrt/LEDE Project
Opened by Marcin Jurkowski - 01.11.2020

FS#3421 - netifd: tries to claim VAP device before it's created

This is obviously a general issue but the problem was reported on Netgear RT6220. There are two 5 GHz (radio1, non-DFS channel) VAPs and five VAPs in total. Netifd debug log is attached.

When netifd tries to claim second 5 GHz VAP (wl1-gst) it fails with error message:

device_claim(447): claim Network device wl1-gst failed: -1

It seems that the second VAP had not been (yet) created by hostapd when netifd tried to claim it as if it lacked a proper synchronization with hostapd.

As a result:

wl1-gst device is never added as bridge member,
it permanently stays in “down” state:

# ubus call network.device status '{ "name": "wl1-gst" }'
{
	"external": true,
	"present": true,
	"type": "Network device",
	"up": false,
	"carrier": true,
	"statistics": {
                ...
	}
}

the second 5 GHz VAP is pretty much useless.

There’s no easy way to workaround this since each wifi reload command triggers the same routine.

Is it possible to fix netifd without a major rewrite? It seems that to consider each VAP ready as soon as hostapd is started, which is obviously not the case.

The problem was originally reported in FS#2698 but the workaround in https://github.com/openwrt/openwrt/pull/2848 treats only some symptoms. The root cause is still unaddressed.