Subject: linux-next: build failure after merge of the modules tree

From: Stephen Rothwell <[email-masked]>
Date: Wed, 24 Jun 2015 11:37:27 +1000

Hi Rusty,

After merging the modules tree, today's linux-next build (x86_64
allmodconfig) failed like this:

In file included from include/linux/linkage.h:4:0,
                 from include/linux/kernel.h:6,
                 from kernel/params.c:18:
kernel/params.c: In function 'param_array':
kernel/params.c:32:42: error: dereferencing pointer to incomplete type
 #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : &param_lock)
                                          ^
include/linux/compiler.h:164:42: note: in definition of macro 'unlikely'
 # define unlikely(x) __builtin_expect(!!(x), 0)
                                          ^
kernel/params.c:462:3: note: in expansion of macro 'BUG_ON'
   BUG_ON(!KPARAM_IS_LOCKED(mod));
   ^
kernel/params.c:33:47: note: in expansion of macro 'KPARAM_MUTEX'
 #define KPARAM_IS_LOCKED(mod) mutex_is_locked(KPARAM_MUTEX(mod))
                                               ^
kernel/params.c:462:11: note: in expansion of macro 'KPARAM_IS_LOCKED'
   BUG_ON(!KPARAM_IS_LOCKED(mod));
           ^
kernel/params.c: In function 'param_array_get':
kernel/params.c:32:42: error: dereferencing pointer to incomplete type
 #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : &param_lock)
                                          ^
include/linux/compiler.h:164:42: note: in definition of macro 'unlikely'
 # define unlikely(x) __builtin_expect(!!(x), 0)
                                          ^
kernel/params.c:499:3: note: in expansion of macro 'BUG_ON'
   BUG_ON(!KPARAM_IS_LOCKED(p.mod));
   ^
kernel/params.c:33:47: note: in expansion of macro 'KPARAM_MUTEX'
 #define KPARAM_IS_LOCKED(mod) mutex_is_locked(KPARAM_MUTEX(mod))
                                               ^
kernel/params.c:499:11: note: in expansion of macro 'KPARAM_IS_LOCKED'
   BUG_ON(!KPARAM_IS_LOCKED(p.mod));
           ^
In file included from include/linux/notifier.h:13:0,
                 from include/linux/memory_hotplug.h:6,
                 from include/linux/mmzone.h:789,
                 from include/linux/gfp.h:5,
                 from include/linux/kmod.h:22,
                 from include/linux/module.h:13,
                 from kernel/params.c:21:
kernel/params.c: In function 'kernel_param_lock':
kernel/params.c:32:42: error: dereferencing pointer to incomplete type
 #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : &param_lock)
                                          ^
include/linux/mutex.h:146:44: note: in definition of macro 'mutex_lock'
 #define mutex_lock(lock) mutex_lock_nested(lock, 0)
                                            ^
kernel/params.c:621:13: note: in expansion of macro 'KPARAM_MUTEX'
  mutex_lock(KPARAM_MUTEX(mod));
             ^
kernel/params.c: In function 'kernel_param_unlock':
kernel/params.c:32:42: error: dereferencing pointer to incomplete type
 #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : &param_lock)
                                          ^
kernel/params.c:626:15: note: in expansion of macro 'KPARAM_MUTEX'
  mutex_unlock(KPARAM_MUTEX(mod));
               ^

Caused by commit b51d23e4e9fe ("module: add per-module param_lock").

I am not exactly sure why this fails to build.  It may be an
interaction with some other change.

I have used the modules tree from next-20150623 for today.

-- 
Cheers,
Stephen Rothwell                    [email-masked]