kernel-packages team mailing list archive

[bugproxy <bugproxy@xxxxxxxxxx>]

------- Comment From hbathini@xxxxxxxxxx 2015-02-06 15:55 EDT-------
(In reply to comment #20)
>
> On 02/04/2015 01:29 PM, bugproxy wrote:
> > Louis & Chris, thanks for your help.
> > The packages work as intended in both kdump & fadump modes.
> > Couple of observations though:
> >
> > 1. When doing load/unload twice in succession, echo throws an error
> >
> > root@lop831:~# kdump-config load
> > * fadump registered successfully
> > root@lop831:~# kdump-config load
> > /usr/sbin/kdump-config: line 301: echo: write error: Invalid argument
> > * fadump registered successfully
> > root@lop831:~#
> > --
> >
> > root@lop831:~# kdump-config unload
> > * fadump un-registered successfully
> > root@lop831:~# kdump-config unload
> > /usr/sbin/kdump-config: line 323: echo: write error: Invalid argument
> > * fadump un-registered successfully
> > root@lop831:~#
> >
>
> The code is where we set values into the sysfs directory:
> echo 1 > $sys_fadump_registered
>
> Where:
> sys_fadump_registered=/sys/kernel/fadump_registered
>
> Hari, can you confirm if kdump-config load/unload are actually changing
> these values correctly? Perhaps the code needs to be adjusted.

Chris, I see the error from cmdline as well,
while echo'ing 1/0 repeatedly to /sys/kernel/fadump_registered.

---

root@lop831:~# cat /sys/kernel/fadump_registered
0
root@lop831:~# echo 1 > /sys/kernel/fadump_registered
root@lop831:~# echo 1 > /sys/kernel/fadump_registered
echo: write error: Invalid argument
root@lop831:~#

---

root@lop831:~# cat /sys/kernel/fadump_registered
1
root@lop831:~# echo 0 > /sys/kernel/fadump_registered
root@lop831:~# echo 0 > /sys/kernel/fadump_registered
echo: write error: Invalid argument
root@lop831:~#

---

It seems to be the way this node is handled in fadump kernel code.
To avoid this error, we could adjust the kdump-config load/unload functions,
to check for the value and set the node only if needed,

for load:
if [ `cat $sys_fadump_registered` != 1 ]
echo 1 >  $sys_fadump_registered

for unload:
if [ `cat $sys_fadump_registered` != 0 ]
echo 0 >  $sys_fadump_registered

I hope this is ok with you..

Thanks
Hari

>
> > 2. While using network dump (SSH), would be nice if we can warn the user to run
> > 'kdump-config propagate' before 'kdump-config load', if /root/.ssh/kdump_id_rsa is missing.
> > This applies to both kdump & fadump modes
> >
> > Thanks
> > Hari
> >
>
> Louis,
> This might be a good general bug/issue to look into.
>
> Thanks,
> --chris
>
> kdump-config propagate is a manual configuration option that needs to remain
> as such. It creates a passwordless ssh key and will propagate to the remote
> ssh server, which most probably will prompt for the remote server's
> password in doing so.
>
> This cannot be done systematically. It also has a direct impact on the
> security of remote servers so it must be an <opt in> requirement from the
> user.

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1415562

Title:
  [Ubuntu 15.04] Support firmware assisted dump on ppc64le

Status in linux package in Ubuntu:
  Fix Committed
Status in makedumpfile package in Ubuntu:
  In Progress

Bug description:
  Starting from POWER6, the firmware now has a capability to preserve
  the partition memory dump during system crash and boot into a fresh
  copy of the kernel with fully-reset system. This feature adds the
  necessary support to exploit the dump capture capability provided by
  Power firmware.  With this feature support, the production kernel will
  register for firmware-assisted dump using RTAS (Runtime Abstraction
  Service) calls and builds required ELF header which then gets exported
  through '/proc/vmcore' in the second kernel after crash.  This feature
  improves Power serviceability by making it more robust compared to
  current kdump mechanism on Linux.

  Ubuntu 15.04 kernel already includes the necessary code for fadump.
  The only kernel change needed is to enable CONFIG_FA_DUMP in the
  kernel configuration. In addition, an update is needed for a script in
  kdump-tools package.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1415562/+subscriptions