From: Stephen Rothwell <sfr@canb•auug.org.au>
To: Jason Wessel <jason.wessel@windriver•com>
Cc: linux-next@vger•kernel.org, linux-kernel@vger•kernel.org
Subject: Re: linux-next: kgdb tree build warning
Date: Thu, 24 Dec 2009 16:21:17 +1100 [thread overview]
Message-ID: <20091224162117.ac18e50f.sfr@canb.auug.org.au> (raw)
In-Reply-To: <4B32E95C.3030201@windriver.com>
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Hi Jason,
On Wed, 23 Dec 2009 22:09:00 -0600 Jason Wessel <jason.wessel@windriver•com> wrote:
>
> Stephen Rothwell wrote:
> >
> > Today's linux-next build (x86_64_allmodconfig) produced this warning:
> >
> > kernel/debug/kdb/kdb_bp.c: In function 'kdb_bp':
> > kernel/debug/kdb/kdb_bp.c:434: warning: the frame size of 32880 bytes is larger than 2048 bytes
> >
> > Introduced by commit 16f40ed7bd0ad29dcde7a05b8a07f5ba10937277 ("kdb: core
> > for kgdb back end").
>
> Using gcc 4.3, I did not see this error. What compiler or compiler
> options did you use to get this?
I use a gcc 4.4.0 cross sompiler for all the x86_64 builds. No special
compiler options apart from those provided by the allmodconfig build.
It looks like the compiler gets -Wframe-larger-than=${CONFIG_FRAME_WARN}
passed to it (and presumably CONFIG_FRAME_WARN is 2048).
> I assume it means the stack space was exhausted and a casual glance at
> the code did not yield anything obvious like a large array on the stack
> or anything. It is conceivable that there is an inline function that is
> the source of the problem, but I would like to be able to duplicate it.
OK.
That function has a kdb_bp_t on its stack which contains an NR_CPUS array
of pointers. NR_CPUS is 4096 (in this build) and pointers are 8 bytes,
so there is 32K right there :-(
--
Cheers,
Stephen Rothwell sfr@canb•auug.org.au
http://www.canb.auug.org.au/~sfr/
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next prev parent reply other threads:[~2009-12-24 5:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-23 23:48 linux-next: kgdb tree build warning Stephen Rothwell
2009-12-24 4:09 ` Jason Wessel
2009-12-24 5:21 ` Stephen Rothwell [this message]
2009-12-24 14:44 ` Jason Wessel
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