[lxc-devel] [PATCH] fix possible 100% cpu loop by fedora template

[Serge Hallyn]

Quoting Michael Adam (obnox at samba.org):
> Another patch to the fedora template.
> 
> My f21 containers ran into a 100% cpu loop for systemd-journald.
> 
> Here is the explanation:
> https://lists.linuxcontainers.org/pipermail/lxc-users/2014-October/007907.html
> 
> I have made the change to set lxc.kmsg = 0 in the generated
> config if the release is using systemd.
> 
> Thanks for consideration,
> 
> Michael
> 

> From df7ca9966936bfcf4aa52a46dd39d594e0709ce1 Mon Sep 17 00:00:00 2001
> From: Michael Adam <obnox at samba.org>
> Date: Fri, 2 Jan 2015 21:12:21 +0100
> Subject: [PATCH] lxc-fedora: when using systemd, set lxc.kmsg = 0 in the
>  config
> 
> This is to prevent systemd-journald to enter a 100% cpu loop.
> 
> Signed-off-by: Michael Adam <obnox at samba.org>

Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>

> ---
>  templates/lxc-fedora.in | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/templates/lxc-fedora.in b/templates/lxc-fedora.in
> index 2123e69..adfaab2 100644
> --- a/templates/lxc-fedora.in
> +++ b/templates/lxc-fedora.in
> @@ -1117,13 +1117,22 @@ lxc.include = @LXCTEMPLATECONFIG@/fedora.common.conf
>  " >> $config_path/config
>      fi
>  
> +    if [ "x$have_systemd" = "x1" ]; then
> +        cat <<EOF >> $config_path/config
> +lxc.autodev = 1
> +lxc.kmsg = 0
> +EOF
> +    else
> +        cat <<EOF >> $config_path/config
> +lxc.autodev = 0
> +EOF
> +    fi
> +
>      # Append things which require expansion here...
>      cat <<EOF >> $config_path/config
>  lxc.arch = $arch
>  lxc.utsname = $utsname
>  
> -lxc.autodev = $auto_dev
> -
>  # When using LXC with apparmor, uncomment the next line to run unconfined:
>  #lxc.aa_profile = unconfined
>  
> @@ -1337,12 +1346,12 @@ if [ -z "$release" ]; then
>      fi
>  fi
>  
> -# Fedora 15 and above run systemd.  We need autodev enabled to keep
> +# Fedora 15 and above run systemd.We need autodev enabled to keep
>  # systemd from causing problems.
> +# Also, kmsg must not be mapped to prevent a 100% cpu loop
> +# in systemd-journald.
>  if [ $release -gt 14 ]; then
> -    auto_dev="1"
> -else
> -    auto_dev="0"
> +    have_systemd="1"
>  fi
>  
>  if [ "$(id -u)" != "0" ]; then
> -- 
> 2.1.0
> 




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