Re: [PATCH 1/2] kdump/fadump: fix network interface name when switching from fadump to kdump

[Hari Bathini]

Hi Dave,

On Monday 12 September 2016 07:35 AM, Dave Young wrote:
> Hi, Hari
>
> Thanks for sending the patches.
>
> The issue will not happen if we restore default initrd in patch 2/2,
> right? So patch 1/2 is not necessary?

Actually, the first reboot after switching over from fadump to kdump
still holds the interface name with "kdump-" prefix as we haven't restored
the default initrd yet. This patch intents to cover that and also, to 
restore
the original interface name for subsequent reboots..

Thanks
Hari
> On 09/07/16 at 06:10pm, Hari Bathini wrote:
> > When a remote dump target is specified, kdump dracut module prefixes
> > 'kdump-' to network interface name (ifname) as kernel assigned names
> > are not persistent. In fadump mode, kdump dracut module is added to
> > the default initrd, which adds the 'kdump-' prefix to the ifname of
> > the prodcution kernel itself. If fadump mode is disabled after this,
> > kdump dracut module picks the ifname that is already prefixed with
> > 'kdump-' in the production kernel and adds another 'kdump-' to it,
> > making the ifname something like kdump-kdump-eth0 for kdump kernel.
> > Eventually, kdump kernel fails with below traces:
> >
> > dracut-initqueue[246]: RTNETLINK answers: Network is unreachable
> >    dracut-initqueue[246]: arping: Device kdump-kdump-eth0 not available.
> >
> > The ip command shows the below:
> >
> > kdump:/# ip addr show kdump-kdump-eth0
> >    2: kdump-kdump-eth: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 \
> >    qdisc pfifo_fast state UNKNOWN qlen 1000
> >        link/ether 22:82:87:7b:98:02 brd ff:ff:ff:ff:ff:ff
> >        inet6 2002:903:15f:550:2082:87ff:fe7b:9802/64 scope global \
> >        mngtmpaddr dynamic
> >           valid_lft 2591890sec preferred_lft 604690sec
> >        inet6 fe80::2082:87ff:fe7b:9802/64 scope link
> >           valid_lft forever preferred_lft forever
> >    kdump:/#
> >
> > The trailing 0 from kdump-kdump-eth0 is missing in the ifname, probably
> > truncated while setting.
> >
> > This patch fixes this by avoiding addition of the prefix 'kdump-' when
> > such prefix is already present in the ifname.
> > Signed-off-by: Hari Bathini
> >
> > dracut-module-setup.sh |    3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> > index 68e0ff8..490501a 100755
> > --- a/dracut-module-setup.sh
> > +++ b/dracut-module-setup.sh
> > @@ -161,7 +161,8 @@ kdump_get_perm_addr() {
> >   kdump_setup_ifname() {
> >       local _ifname
> > if [[ $1 =~ eth* ]]; then
> > # If ifname has 'kdump-' prefix, don't add it again
> > if [[ $1 =~ eth* ]] && [[ ! $1 =~ ^kdump-* ]]; then
> >      _ifname="kdump-$1"
> >  else
> >      _ifname="$1"
> >
> > kexec mailing list
> > [e-mail]
> > https://lists.fedoraproject.org/admin/lists/[e-mail]
>
> Thanks
> Dave