Re: include/linux/kernel.h:860:32: error: dereferencing pointer to incomplete type 'struct clock_event_device'

From: Ian Abbott
Date: Mon Sep 25 2017 - 11:06:53 EST


On 24/09/17 09:26, kbuild test robot wrote:
Hi Ian,

FYI, the error/warning still remains.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: cd4175b11685b11c40e31a03e05084cc212b0649
commit: c7acec713d14c6ce8a20154f9dfda258d6bcad3b kernel.h: handle pointers to arrays better in container_of()
date: 2 months ago
config: ia64-allmodconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 6.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
git checkout c7acec713d14c6ce8a20154f9dfda258d6bcad3b
# save the attached .config to linux build tree
make.cross ARCH=ia64

All errors (new ones prefixed by >>):

In file included from drivers/clocksource/timer-of.c:25:0:
drivers/clocksource/timer-of.h:35:28: error: field 'clkevt' has incomplete type
struct clock_event_device clkevt;
^~~~~~

That's the first compile error - 'struct clock_event_device' is incomplete because 'CONFIG_GENERIC_CLOCKEVENTS' is not defined.

In file included from include/linux/err.h:4:0,
from include/linux/clk.h:15,
from drivers/clocksource/timer-of.c:18:
drivers/clocksource/timer-of.h: In function 'to_timer_of':
include/linux/kernel.h:860:32: error: dereferencing pointer to incomplete type 'struct clock_event_device'
BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
^~~~~~
include/linux/compiler.h:517:19: note: in definition of macro '__compiletime_assert'
bool __cond = !(condition); \
^~~~~~~~~
include/linux/compiler.h:537:2: note: in expansion of macro '_compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:46:37: note: in expansion of macro 'compiletime_assert'
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^~~~~~~~~~~~~~~~~~
include/linux/kernel.h:860:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
^~~~~~~~~~~~~~~~
include/linux/kernel.h:860:20: note: in expansion of macro '__same_type'
BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
^~~~~~~~~~~
drivers/clocksource/timer-of.h:44:9: note: in expansion of macro 'container_of'
return container_of(clkevt, struct timer_of, clkevt);
^~~~~~~~~~~~
--
In file included from drivers//clocksource/timer-of.c:25:0:
drivers//clocksource/timer-of.h:35:28: error: field 'clkevt' has incomplete type
struct clock_event_device clkevt;
^~~~~~
In file included from include/linux/err.h:4:0,
from include/linux/clk.h:15,
from drivers//clocksource/timer-of.c:18:
drivers//clocksource/timer-of.h: In function 'to_timer_of':
include/linux/kernel.h:860:32: error: dereferencing pointer to incomplete type 'struct clock_event_device'
BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
^~~~~~
include/linux/compiler.h:517:19: note: in definition of macro '__compiletime_assert'
bool __cond = !(condition); \
^~~~~~~~~
include/linux/compiler.h:537:2: note: in expansion of macro '_compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:46:37: note: in expansion of macro 'compiletime_assert'
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^~~~~~~~~~~~~~~~~~
include/linux/kernel.h:860:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
^~~~~~~~~~~~~~~~
include/linux/kernel.h:860:20: note: in expansion of macro '__same_type'
BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
^~~~~~~~~~~
drivers//clocksource/timer-of.h:44:9: note: in expansion of macro 'container_of'
return container_of(clkevt, struct timer_of, clkevt);
^~~~~~~~~~~~

vim +860 include/linux/kernel.h

843
844
845 /*
846 * swap - swap value of @a and @b
847 */
848 #define swap(a, b) \
849 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
850
851 /**
852 * container_of - cast a member of a structure out to the containing structure
853 * @ptr: the pointer to the member.
854 * @type: the type of the container struct this is embedded in.
855 * @member: the name of the member within the struct.
856 *
857 */
858 #define container_of(ptr, type, member) ({ \
859 void *__mptr = (void *)(ptr); \
> 860 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
861 !__same_type(*(ptr), void), \
862 "pointer type mismatch in container_of()"); \
863 ((type *)(__mptr - offsetof(type, member))); })
864

---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation


Cc'ing Daniel Lezcano and Thomas Gleixner, since this seems to be a problem with configurations selecting 'TIMER_OF' even though 'GENERIC_CLOCKEVENTS' is not selected.

There was a recent-ish commit 599dc457c79b ("clocksource/drivers/Kconfig: Fix CLKSRC_PISTACHIO dependencies") to address this problem for one particular clocksource driver, but some other clocksource drivers seem to share the same problem. There are several clocksource config options in "drivers/clocksource/Kconfig" that select 'TIMER_OF' without depending on 'GENERIC_CLOCKEVENTS'. Some of them are only manually selectable when 'COMPILE_TEST' is selected. This particular failure seems to be at least partly due to 'ARMV7M_SYSTICK' getting selected.

--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Web: http://www.mev.co.uk/ )=-