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Message-ID: <8faa14caf032ea11fc329eeefa11f0f7159b13a4.camel@sipsolutions.net>
Subject: Re: [PATCH] mac80211: mesh: only warn if mesh peering is established
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Markus Theil <markus.theil@tu-ilmenau.de>
Cc:     linux-wireless@vger.kernel.org
Date:   Fri, 13 Dec 2019 10:13:39 +0100
In-Reply-To: <20191203180644.70653-1-markus.theil@tu-ilmenau.de>
References: <20191203180644.70653-1-markus.theil@tu-ilmenau.de>
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On Tue, 2019-12-03 at 19:06 +0100, Markus Theil wrote:
> The following warning is triggered every time an unestablished mesh peer
> gets dumped. This patch checks, if a peer link is established, when dum-
> ping the airtime link metric.
> 
> [ 9563.022567] WARNING: CPU: 0 PID: 6287 at net/mac80211/mesh_hwmp.c:345
>                airtime_link_metric_get+0xa2/0xb0 [mac80211]
> [ 9563.022697] Hardware name: PC Engines apu2/apu2, BIOS v4.10.0.3
> [ 9563.022756] RIP: 0010:airtime_link_metric_get+0xa2/0xb0 [mac80211]
> [ 9563.022838] Call Trace:
> [ 9563.022897]  sta_set_sinfo+0x936/0xa10 [mac80211]
> [ 9563.022964]  ieee80211_dump_station+0x6d/0x90 [mac80211]
> [ 9563.023062]  nl80211_dump_station+0x154/0x2a0 [cfg80211]
> [ 9563.023120]  netlink_dump+0x17b/0x370
> [ 9563.023130]  netlink_recvmsg+0x2a4/0x480
> [ 9563.023140]  ____sys_recvmsg+0xa6/0x160
> [ 9563.023154]  ___sys_recvmsg+0x93/0xe0
> [ 9563.023169]  __sys_recvmsg+0x7e/0xd0
> [ 9563.023210]  do_syscall_64+0x4e/0x140
> [ 9563.023217]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

OK, I can see how this happens.

However,

> +	if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
> +		return MAX_METRIC;
> +

I'm not really sure this is the right way to fix it?

I'm sure you observed this only when the link isn't established yet, but
it seems to me that even when a link is established it could still
happen?

Or are the frames that are necessary for link establishment enough to
always set the metric?

johannes