From: Jakub Kicinski <kuba@kernel.org>
To: Thomas Osterried <thomas@osterried.de>
Cc: Eric Dumazet <edumazet@google.com>,
"David S . Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>, Bernard Pidoux <f6bvp@free.fr>,
Duoming Zhou <duoming@zju.edu.cn>,
netdev@vger.kernel.org, linux-hams@vger.kernel.org
Subject: Re: [AX25] patch did not fix -- was: ax25: fix incorrect dev_tracker usage
Date: Mon, 24 Oct 2022 13:56:40 -0700 [thread overview]
Message-ID: <20221024135640.73e5eddf@kernel.org> (raw)
In-Reply-To: <2B6541B7-FF35-41D2-8A20-18D5EEE7A919@osterried.de>
On Mon, 24 Oct 2022 20:00:00 +0200 Thomas Osterried wrote:
> II) What consequences has the tracker counter?
>
> As far as I can see by kernel messages, the netdev tracker forces the
> kernel to wait
> (on ifdown (i.e. ifconfig ax0 down)
> or rmmod (i.e. rmmod bpqether or rmmod ax25) )
> until all references to the network device are freed.
> If there's a bug (refcount > 0 or < 0), kernel obviously waits for ever.
Small correction here - the wait is when netdev is unregistered,
which often happens on rmmod, but also when user asks for a sw
netdev to be deleted, or HW device is removed, etc.
> III) Is it only to track sessions initiated from userspace?
>
> I think no.
Correct, the trackers track the references taken on the device.
Doesn't really matter if the reference is somehow tracable to
a user request or not.
Sorry for lack of input on the actual ax25 problem, I had looked
briefly in September and it wasn't obvious how things work :S
prev parent reply other threads:[~2022-10-24 20:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-10 7:16 [AX25] patch did not fix -- was: ax25: fix incorrect dev_tracker usage Thomas Osterried
2022-09-10 11:49 ` Thomas Osterried
2022-10-24 18:00 ` Thomas Osterried
2022-10-24 20:56 ` Jakub Kicinski [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20221024135640.73e5eddf@kernel.org \
--to=kuba@kernel.org \
--cc=davem@davemloft.net \
--cc=duoming@zju.edu.cn \
--cc=edumazet@google.com \
--cc=f6bvp@free.fr \
--cc=linux-hams@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=thomas@osterried.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).