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Subject: Re: [PATCH] ubifs: fix kconfig dependency warning
From: Artem Bityutskiy <dedekind1@gmail.com>
To: Randy Dunlap <randy.dunlap@oracle.com>
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Date: Tue, 29 Mar 2011 10:02:58 +0300
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Cc: linux-mtd@lists.infradead.org, lkml <linux-kernel@vger.kernel.org>,
	Adrian Hunter <adrian.hunter@nokia.com>
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On Mon, 2011-03-28 at 13:40 -0700, Randy Dunlap wrote:
> From: Randy Dunlap <randy.dunlap@oracle.com>
> 
> Fix another kconfig dependency warning, this time in ubifs.
> 
> warning: (UBIFS_FS_DEBUG && LOCKDEP && LATENCYTOP) selects KALLSYMS_ALL which has unmet direct dependencies (DEBUG_KERNEL && KALLSYMS)
> 
> Without this patch, we can have:
> # CONFIG_KALLSYMS is not set
> CONFIG_KALLSYMS_ALL=y
> which is useless (does nothing unless KALLSYMS is enabled).
> 
> However, ubifs builds successfully with or without this patch,
> and it builds with this line completely deleted,
> so what was this 'select' for?  Just developer convenience?

Well, here is the idea. You can compile UBIFS with debugging and without
debugging. Without debugging the resulting ubifs.ko is much smaller, so
some embedded people prefer it this way.

If you select debugging support, then we'll compile it a lot of
assertions, self-checks, test-modes, extra error messages with detailed
dumps. And we want to see stackdumps when errors or problems happen,
this is why we select KALLSYMS_ALL.

So I guess instead we should do:

select KALLSYMS
select KALLSYMS_ALL

?

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)