Re: [LTP] [RFC] autokdump - automated kdump testsuite

CAI Qian
2014-09-22T13:00:31Z

----- Original Message -----
> From: "Vivek Goyal" <vgoyal@redhat.com>
> To: "CAI Qian" <caiqian@redhat.com>
> Cc: "linux-kernel" <linux-kernel@vger.kernel.org>, "ltp-list" <ltp-list@lists.sourceforge.net>, "crash-utility"
> <crash-utility@redhat.com>, "kexec" <kexec@lists.infradead.org>, "kexec kdump redhat mailing list"
> <kexec-kdump-list@redhat.com>
> Sent: Friday, September 19, 2014 9:22:36 PM
> Subject: Re: [RFC] autokdump - automated kdump testsuite
>
> On Fri, Sep 19, 2014 at 05:52:25AM -0400, CAI Qian wrote:
> > I plan to release an automated kdump testsuite that will be
>
> So will this be a standalone test suit? Can it be merged with
> something already existing say, LTP.
Yes, it is likely to be standalone. It won't make use of the LTP
API, and the LTP kdump test suite is outdated, so there is no
benefit to continue working over there.
>
> > focus on testing kernel and the crash utility. It should work
> > for all major distros since it will use none of distro-specific
> > stuff, and also support different arches including x86, ARM,
> > PPC64 and s390x.
> >
> > It does the following:
> > 1) check if there is a memory reserved for kdump. If not,
> > reserve the memory and reboot the system.
> > 2) once the system is back, load kexec on panic and
> > prepare a separate initramfs that including needed
> > modules to load a local filesystem and necessary utilities
>
> So you will write logic to prepare custom initramfs or will rely
> on dracut or some other utility for that.
I'll probably prepare custom initramfs for the sake of simplicity.
>
> > in order to analyse /proc/vmcore in the 2nd kernel.
> > 3) trigger the system crash using methods like sysrq-c, NMI,
> > and panic_on_hung_task etc.
> > 4) in the 2nd kernel, mount a filesystem and use the crash
> > utility to analyse /proc/vmcore. Then, gather the analyse
> > logs, serial console output, dmesg etc into the filesystem.
>
> Why not save core and boot back in first kernel and then analyze.
>
> Trying to work directly with /proc/vmcore does not test makedumfile
> which everybody uses. Also it will require more memory to be reserved
> and packing crash and debug vmlinux into initramfs.
The additional memory for vmlinux and the crash utility is predictable
and manageable, so it can just ask 256M memory reserved before running
the program. On the other hand, it is not usually feasible to ask
the systems under testing has enough available disk spaces bigger than
the memory size.
CAI Qian
>
> I think being able to test makedumpfile also is the key here.
>
> Thanks
> Vivek
> > 5) reboot back into the 1st kernel.
> >
> > implementation:
> > It will setup a daemon to handle reboots.
> >
> > plan:
> > I might also to test the makedumpfile all together later.
> > CAI Qian