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

[Hari Bathini]

On Monday 12 September 2016 10:08 PM, Hari Bathini wrote:
>  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..
>  
Ignore the 2nd use-case as patch 2/2 covers this anyway..

Alternatively, to cover the 1st use-case, we can relay on the
GUI script by restoring initrd as and when fadump is disabled in GUI.
I feel the below hunk is harmless though..

Thanks
Hari

>  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 <hbathini(a)linux.vnet.ibm.com&gt;
> >> ---
> >>   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
> >> kexec(a)lists.fedoraproject.org
> >> https://lists.fedoraproject.org/admin/lists/[e-mail] 
> >>
> > Thanks
> > Dave
> >
>  _______________________________________________
>  kexec mailing list
>  kexec(a)lists.fedoraproject.org
>  https://lists.fedoraproject.org/admin/lists/[e-mail]