From: Jakub Kicinski <kuba@kernel.org>
To: netdev@vger.kernel.org
Cc: Florian Westphal <fw@strlen.de>,
Aleksandr Nogikh <nogikh@google.com>,
syzbot <syzbot+9bbbacfbf1e04d5221f7@syzkaller.appspotmail.com>,
dsterba@suse.cz, bakmitopiacibubur@boga.indosterling.com,
clm@fb.com, davem@davemloft.net, dsahern@kernel.org,
dsterba@suse.com, gregkh@linuxfoundation.org,
jirislaby@kernel.org, josef@toxicpanda.com, kadlec@netfilter.org,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
linux@armlinux.org.uk, netfilter-devel@vger.kernel.org,
pablo@netfilter.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [btrfs?] [netfilter?] BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! (2)
Date: Wed, 19 Jul 2023 20:30:30 -0700 [thread overview]
Message-ID: <20230719203030.1296596a@kernel.org> (raw)
In-Reply-To: <20230719231207.GF32192@breakpoint.cc>
On Thu, 20 Jul 2023 01:12:07 +0200 Florian Westphal wrote:
> I don't see any netfilter involvement here.
>
> The repro just creates a massive amount of team devices.
>
> At the time it hits the LOCKDEP limits on my test vm it has
> created ~2k team devices, system load is at +14 because udev
> is also busy spawing hotplug scripts for the new devices.
>
> After reboot and suspending the running reproducer after about 1500
> devices (before hitting lockdep limits), followed by 'ip link del' for
> the team devices gets the lockdep entries down to ~8k (from 40k),
> which is in the range that it has on this VM after a fresh boot.
>
> So as far as I can see this workload is just pushing lockdep
> past what it can handle with the configured settings and is
> not triggering any actual bug.
The lockdep splat because of netdevice stacking is one of our top
reports from syzbot. Is anyone else feeling like we should add
an artificial but very high limit on netdev stacking? :(
next prev parent reply other threads:[~2023-07-20 3:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000a054ee05bc4b2009@google.com>
2023-07-19 9:32 ` [syzbot] [btrfs?] [netfilter?] BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! (2) syzbot
2023-07-19 17:04 ` David Sterba
2023-07-19 17:11 ` syzbot
2023-07-19 17:14 ` Aleksandr Nogikh
2023-07-19 23:12 ` Florian Westphal
2023-07-20 3:30 ` Jakub Kicinski [this message]
2023-07-20 7:18 ` Paolo Abeni
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=20230719203030.1296596a@kernel.org \
--to=kuba@kernel.org \
--cc=bakmitopiacibubur@boga.indosterling.com \
--cc=clm@fb.com \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=dsterba@suse.com \
--cc=dsterba@suse.cz \
--cc=fw@strlen.de \
--cc=gregkh@linuxfoundation.org \
--cc=jirislaby@kernel.org \
--cc=josef@toxicpanda.com \
--cc=kadlec@netfilter.org \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=nogikh@google.com \
--cc=pablo@netfilter.org \
--cc=syzbot+9bbbacfbf1e04d5221f7@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
/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).