From: Markus Theil <markus.theil@tu-ilmenau.de>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org
Subject: Re: [PATCH] mac80211: mesh: only warn if mesh peering is established
Date: Sat, 14 Dec 2019 11:13:05 +0100 [thread overview]
Message-ID: <e29d43cc-0e72-38af-6c07-5c32dca872d9@tu-ilmenau.de> (raw)
In-Reply-To: <8faa14caf032ea11fc329eeefa11f0f7159b13a4.camel@sipsolutions.net>
On 12/13/19 10:13 AM, Johannes Berg wrote:
> 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
The current mac80211 code initializes this moving average when setting
the peer link to established in sta_apply_mesh_params.
case NL80211_PLINK_ESTAB:
...
ewma_mesh_tx_rate_avg_init(&sta->mesh->tx_rate_avg);
/* init at low value */
ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg, 10);
break;
This ewma_mesh_tx_rate_avg_add is the only reference that I found in the
code. It seems, that this avg is only initialized and never updated
during the plink lifetime.
--
Markus Theil
Technische Universität Ilmenau, Fachgebiet Telematik/Rechnernetze
Postfach 100565
98684 Ilmenau, Germany
Phone: +49 3677 69-4582
Email: markus[dot]theil[at]tu-ilmenau[dot]de
Web: http://www.tu-ilmenau.de/telematik
next prev parent reply other threads:[~2019-12-14 10:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 18:06 [PATCH] mac80211: mesh: only warn if mesh peering is established Markus Theil
2019-12-13 9:13 ` Johannes Berg
2019-12-14 10:13 ` Markus Theil [this message]
2019-12-14 15:51 ` Markus Theil
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