linux-kernel - Re: [PATCH 11/13] kexec-bzImage: Support for loading bzImage using 64bit entry

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Message-ID: <20140616214523.GC1870@redhat.com>
Date:	Mon, 16 Jun 2014 17:45:23 -0400
From:	Vivek Goyal <vgoyal@...hat.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
	ebiederm@...ssion.com, hpa@...or.com, mjg59@...f.ucam.org,
	greg@...ah.com, jkosina@...e.cz, dyoung@...hat.com,
	chaowang@...hat.com, bhe@...hat.com, akpm@...ux-foundation.org
Subject: Re: [PATCH 11/13] kexec-bzImage: Support for loading bzImage using
 64bit entry

On Mon, Jun 16, 2014 at 11:27:20PM +0200, Borislav Petkov wrote:
> On Mon, Jun 16, 2014 at 05:15:00PM -0400, Vivek Goyal wrote:
> > Do we want to show all the rejection messages from bzImage64 and
> > bzImage32 loaders. It might be too verbose to show users that before
> > vmlinux loader accepted the image other loaders on this arches rejcted
> > the image.
> 
> I get all that. But, if people want to get feedback from the system
> about *why* their image didn't load, they absolutely have to enable
> dynamic debug. And this is not optimal IMO because they will have to
> look at the code first to see what they need to do.
> 
> Or is kexec-tools going to be taught to interpret return values from the
> syscall?

In most of the cases return code is -ENOEXEC so kexec-tools can't figure
out what's wrong.

> 
> In any case, we want information about why an image fails loading to
> reach the user in the easiest way possible. And why should the user need
> to enable dynamic debug if he can get the info without doing so?
> 
> Oh, and not everyone knows about dynamic debug so...
> 
> And I don't think it'll be too much info - only the line which fails
> the check will be printed before the image loader fails so that's
> practically one error reason per failed image.
> 

Ok, there will be one line of error and that's not too bad. I will
convert these pr_debug() statements in bzImage_probe() to pr_err().

Thanks
Vivek
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