From: Herbert Xu <herbert@gondor.apana.org.au>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: harald@skogtun.org, johannes@sipsolutions.net,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [BISECTED] 5.12 hangs at reboot
Date: Tue, 27 Apr 2021 15:43:21 +0800 [thread overview]
Message-ID: <20210427074321.callv22dm4drb2jn@gondor.apana.org.au> (raw)
In-Reply-To: <CAHk-=wjjBEkOdj=C2HxjFu0zaKT46Yw52t7PyCCYFRaFdu57Sw@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> At a guess, there is some other sequence that takes the rtnl lock, and
> then takes the wiphy_lock inside of it, and we have a ABBA deadlock.
The most common cause of these lockups is a stray reference on
some kind of a network object, e.g., a socket or some such. This
then causes the underlying network device to be reference counted
and triggers a lock-up if that network device needs to be removed.
> I _hate_ that stupid rtnl lock. It's come up before. Several times.
> It's probably the most broken lock in the kernel.
Yes, it's the networking equivalent of the BKL.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2021-04-27 7:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-26 18:43 [BISECTED] 5.12 hangs at reboot Harald Arnesen
2021-04-26 18:59 ` Linus Torvalds
2021-04-26 19:19 ` Johannes Berg
2021-04-26 20:23 ` Harald Arnesen
2021-04-26 19:29 ` Harald Arnesen
2021-04-26 19:38 ` Johannes Berg
2021-04-26 19:45 ` Linus Torvalds
2021-04-26 19:46 ` Johannes Berg
2021-04-26 19:51 ` Linus Torvalds
2021-04-26 20:11 ` Johannes Berg
2021-04-26 20:25 ` Harald Arnesen
[not found] ` <151b7e41-a415-e780-eb90-6ca16c113066@skogtun.org>
2021-04-26 22:49 ` Linus Torvalds
2021-04-27 7:43 ` Herbert Xu [this message]
2021-04-27 8:49 ` Johannes Berg
2021-04-26 20:10 ` Harald Arnesen
2021-04-26 20:26 ` Johannes Berg
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