linux-kernel - Re: [PATCH] print kdump kernel loaded status in stack dump

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Message-ID: <20180117104844.7ae779d2@gandalf.local.home>
Date:   Wed, 17 Jan 2018 10:48:44 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Dave Young <dyoung@...hat.com>, sergey.senozhatsky@...il.com,
        linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
        kexec@...ts.infradead.org, Tejun Heo <tj@...nel.org>
Subject: Re: [PATCH] print kdump kernel loaded status in stack dump

On Wed, 17 Jan 2018 14:42:17 +0100
Petr Mladek <pmladek@...e.com> wrote:

> > kexec_crash_loaded is enough, we only care if kdump kernel being
> > loaded or not, nothing else, no matter how long it has been loaded.
> > In Fedora/RHEL a kdump service takes care of loading the kernel but
> > it runs after networking is ready.  If people want to save
> > the vmcore to nfs/ssh then we need detect network and build the
> > initramfs. In the nfs/ssh case if some networking code panicked it
> > is possible that kdump service has not started, but sometimes bug
> > can not be easily reproduced thus nobody can know if kdump is active
> > or not.  
> 
> I see.
> 
> > Since kexec_crash_loaded() is already in kexec souce code, and it
> > is the only thing need to know, do you think it is really necessary
> > to add a printk_kexec_info()?  I can do it if you strongly suggest
> > to do so.  
> 
> No, the original approach is fine if it is really that simple ;-)

I have to ask. Why is dump_stack_print_info() in printk to begin with.
It seems to be an odd place to put it, and not something I would think
should be in the printk() subsystem anyway. Why is it not in
lib/dump_stack.c?


> 
> > > 
> > > Finally, the style of the other lines is:
> > > 
> > >     Name: details
> > > 
> > > I would suggest to print something like:
> > > 
> > >     Kexec: details
> > > 
> > > , where the details might be whether the image is loaded,
> > > whether the loaded kernel is being executed, and
> > > other kexec-related flags.  
> > 
> > Will do, it can be something like:
> > Kexec: kdump kernel loaded  
> 
> Looks good to me. With this message, I could give this
> patch even
> 
> Reviewed-by: Petr Mladek <pmladek@...e.com>
> 
> I could update the string when pushing into printk.git.
> I am just going to wait a bit for more feedback if any.

The patch looks fine to me.

Reviewed-by: Steven Rostedt (VMware) <rostedt@...dmis.org>

-- Steve