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Date:   Fri, 2 Mar 2018 16:54:54 +0100
From:   Petr Mladek <pmladek@suse.com>
To:     Stephen Rothwell <sfr@canb.auug.org.au>
Cc:     Linux-Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Dave Young <dyoung@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        akpm@linux-foundation.org, Andi Kleen <ak@linux.intel.com>
Subject: Re: linux-next: build failure after merge of the printk tree
Message-ID: <20180302155454.eme5gplxdcltvwkw@pathway.suse.cz>
References: <20180302160732.12691fbc@canb.auug.org.au>
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On Fri 2018-03-02 16:07:32, Stephen Rothwell wrote:
> Hi Petr,
> 
> After merging the printk tree, today's linux-next build (bfin
> BF518F-EZBRD_defconfig) failed like this:
> 
> lib/dump_stack.o: In function `dump_stack':
> lib/dump_stack.c:122: multiple definition of `dump_stack'
> arch/blackfin/kernel/dumpstack.o:arch/blackfin/kernel/dumpstack.c:166: first defined here
> 
> Presumably caused by commit
> 
>   8040af489957 ("printk: move dump stack related code to lib/dump_stack.c")

I could confirm that it is caused by this commit. I have temporary
removed it from printk.git.

> (Though it is not immediately obvious why.)

It is a mistery to me. The error appears when I move any of
dump_stack_print_info() or show_regs_print_info() function
definitions from kernel/printk/printk.c to lib/dump_stack.c.
All the other changes seems unrelated.

The thing is that we basically do not touch dump_stack() definition
by that patch.

> This fails all the blackfin builds.  nds32 (a new architecture) also
> has a dump_stack function.

Good to know!

Best Regards,
Petr