On Tue, 23 Oct 2012 14:42:21 +1100
Stephen Rothwell [off-list ref] wrote:

Hi Andrew,

After merging the akpm tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:

kernel/printk/printk_syslog.c: In function 'printk_syslog_print':
kernel/printk/printk_syslog.c:108:3: error: implicit declaration of function 'copy_to_user' [-Werror=implicit-function-declaration]
kernel/printk/printk_syslog.c: In function 'do_syslog':
kernel/printk/printk_syslog.c:245:3: error: implicit declaration of function 'access_ok' [-Werror=implicit-function-declaration]
kernel/printk/printk_syslog.c:245:18: error: 'VERIFY_WRITE' undeclared (first use in this function)
kernel/printk/printk_syslog.c:245:18: note: each undeclared identifier is reported only once for each function it appears in

Caused by commit 598815e5f25f ("printk: add printk_syslog.c and .h").

Presumably missing an (or some) include files - see Rule 1 in
Documentation/SubmitChecklist.

I have reverted that commit for today (and the following commit
2cf91e0e4b9f ("printk: move kmsg_dump functions to separate file")).

I'll add the include.

btw, what's up with printk_syslog.h?  It includes two header files which it
doesn't need but fails to include the two it *does* need: printk_log.h
and types.h.