BPF Archive on lore.kernel.org
 help / color / Atom feed
From: Daniel Borkmann <daniel@iogearbox.net>
To: Rudi Ratloser <reimth@gmail.com>, bpf@vger.kernel.org
Subject: Re: BUG: kernel NULL pointer dereference in __cgroup_bpf_run_filter_skb
Date: Tue, 30 Jun 2020 16:56:37 +0200
Message-ID: <b62a18d0-1f78-3bf5-38b2-08d9a779e432@iogearbox.net> (raw)
In-Reply-To: <CAOLRBTUSkRbku25rbw6Fyb019wFqFvEN=6xGM+RgFJFQ=NH4KQ@mail.gmail.com>

On 6/30/20 4:28 PM, Rudi Ratloser wrote:
> We have experienced a kernel BPF null pointer dereference issue on all
> our machines since mid of June. It might be related to an upgrade of
> libvirt/kvm/qemu at that point of time. But we’re not sure.
> 
> None of the servers can be used with this bug, as they crash latest
> one hour after reboot. The time period until kernel panic can be
> easily reduced down to 2 minutes, when starting one or more
> applications of the following list:
> - LXD daemon (4.2.1)
> - libvirtd daemon (6.4.0) with qemu/kvm guests
> - NFS server 2.5.1
> - Mozilla Firefox
> - Mozilla Thunderbird
> 
> If none of the applications run, the systems seem to be stable.
> 
> Intermediate solution:
> Downgrade Linux kernel to 4.9.226 LTS or 4.4.226  LTS on all the machines
> 
> Why this solution works is not clear, yet. One of the major
> differences we saw is, that both kernel packages have been configured
> with user namespaces disabled.
> 
> We experienced the kernel freeze on following Arch Linux kernels:
> - 5.7.0 (5.7.0-3-MANJARO x64)
> - 5.6.16 (5.6.16-1-MANJARO x64)
> - 5.4.44 (5.4.44-1-MANJARO x64)
> - 4.19.126 (4.19.126-1-MANJARO x64)
> - 4.14.183 (4.14.183-1-MANJARO x64)
> Kernel configs can be taken from https://gitlab.manjaro.org/packages/core.
> 
> Subsequent e-mails will contain the relevant extracts from journal or
> netconsole logs.
> 
> Help and support on this issue is welcome.

Fix is under discussion here:

   https://lore.kernel.org/netdev/20200616180352.18602-1-xiyou.wangcong@gmail.com/

Thanks,
Daniel

  reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30 14:28 Rudi Ratloser
2020-06-30 14:56 ` Daniel Borkmann [this message]
2020-07-01  7:08   ` Thomas Reim
2020-07-01  6:46 ` Thomas Reim
2020-07-01  6:51 ` Thomas Reim
2020-07-01  6:58 ` Thomas Reim
  -- strict thread matches above, loose matches on Subject: below --
2020-06-30 15:11 Rudi Ratloser
     [not found] <20200530074608.GA60664@fnst.localdomain>
2020-06-02 21:46 ` Brenden Blanco
2020-06-02 22:17   ` Alexei Starovoitov
2020-06-03  6:20     ` Lu Fengqi
2020-06-03  8:22       ` Lu Fengqi
2020-06-09 20:50     ` Daniel Borkmann
2020-06-10  1:37       ` Zefan Li
2020-06-03  6:16   ` Lu Fengqi

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=b62a18d0-1f78-3bf5-38b2-08d9a779e432@iogearbox.net \
    --to=daniel@iogearbox.net \
    --cc=bpf@vger.kernel.org \
    --cc=reimth@gmail.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

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org
	public-inbox-index bpf

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git