Re: linux-next: build failure after merge of the ftrace tree

From: Jiri Kosina
Date: Fri Nov 21 2014 - 05:50:24 EST

On Fri, 21 Nov 2014, Stephen Rothwell wrote:

> Hi Steven,
> After merging the ftrace tree, today's linux-next build (powerpc
> allnoconfig) failed like this:
> In file included from include/asm-generic/percpu.h:6:0,
> from arch/powerpc/include/asm/percpu.h:19,
> from include/linux/percpu.h:11,
> from include/linux/sched.h:41,
> from arch/powerpc/kernel/asm-offsets.c:17:
> include/linux/percpu.h:138:17: error: 'printk_func_t' undeclared here (not in a function)
> DECLARE_PER_CPU(printk_func_t, printk_func);
> ^
> include/linux/percpu-defs.h:101:38: note: in definition of macro 'DECLARE_PER_CPU_SECTION'
> extern __PCPU_ATTRS(sec) __typeof__(type) name
> ^
> include/linux/percpu.h:138:1: note: in expansion of macro 'DECLARE_PER_CPU'
> DECLARE_PER_CPU(printk_func_t, printk_func);
> ^

From: Jiri Kosina <jkosina@xxxxxxx>
Subject: [PATCH] printk: make sure printk_func_t is known in percpu.h

Commit afdc34a3d3b8 ("printk: Add per_cpu printk func to allow printk to
be diverted") caused percpu variable printk_func to be declared in
percpu.h. Make sure that the corresponding type is known at the time of

Fixes build failure on certain arch/config combinations.

Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
include/linux/percpu.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index a3aa63e..c94c766 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -7,6 +7,7 @@
#include <linux/cpumask.h>
#include <linux/pfn.h>
#include <linux/init.h>
+#include <linux/printk.h>

#include <asm/percpu.h>

Jiri Kosina
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