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

[Hari Bathini]

On Monday 12 September 2016 10:18 PM, Hari Bathini wrote:
> 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..

Hi Dave,

Another possible case is rebuild may not happen on switching from fadump 
to kdump,
if config files are not changed. I could restore as part of start_dump() 
but that doesn't
sound right to me. Posted v2 with this patch intact. Please review..

Thanks
Hari
> 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
> > > >
> > > > 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
> >
> > kexec mailing list
> > [e-mail]
> > https://lists.fedoraproject.org/admin/lists/[e-mail]
>
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