[memcg:since-4.10 522/528] include/asm-generic/atomic-instrumented.h:70: undefined reference to `__arch_atomic_add_unless'

[memcg:since-4.10 522/528] include/asm-generic/atomic-instrumented.h:70: undefined reference to `__arch_atomic_add_unless'

[kbuild test robot]

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Hi Andrew,

It's probably a bug fix that unveils the link errors.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git since-4.10
head:   7ef887134f52395c4883daddf957aa055578c215
commit: e8bbed4699bb09d2437998bce09c6d8aa20d5963 [522/528] x86-atomic-move-__atomic_add_unless-out-of-line-fix
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        git checkout e8bbed4699bb09d2437998bce09c6d8aa20d5963
        # save the attached .config to linux build tree
        make ARCH=um SUBARCH=x86_64

All errors (new ones prefixed by >>):

   kernel/built-in.o: In function `__atomic_add_unless':
>> include/asm-generic/atomic-instrumented.h:70: undefined reference to `__arch_atomic_add_unless'
>> include/asm-generic/atomic-instrumented.h:70: undefined reference to `__arch_atomic_add_unless'
>> include/asm-generic/atomic-instrumented.h:70: undefined reference to `__arch_atomic_add_unless'
>> include/asm-generic/atomic-instrumented.h:70: undefined reference to `__arch_atomic_add_unless'
>> include/asm-generic/atomic-instrumented.h:70: undefined reference to `__arch_atomic_add_unless'
   kernel/built-in.o:include/asm-generic/atomic-instrumented.h:70: more undefined references to `__arch_atomic_add_unless' follow
   collect2: error: ld returned 1 exit status

vim +70 include/asm-generic/atomic-instrumented.h

6a9463f1 Dmitry Vyukov 2017-03-15  64  	return arch_atomic64_cmpxchg(v, old, new);
6a9463f1 Dmitry Vyukov 2017-03-15  65  }
6a9463f1 Dmitry Vyukov 2017-03-15  66  
6a9463f1 Dmitry Vyukov 2017-03-15  67  static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u)
6a9463f1 Dmitry Vyukov 2017-03-15  68  {
d6c79f35 Dmitry Vyukov 2017-03-15  69  	kasan_check_write(v, sizeof(*v));
6a9463f1 Dmitry Vyukov 2017-03-15 @70  	return __arch_atomic_add_unless(v, a, u);
6a9463f1 Dmitry Vyukov 2017-03-15  71  }
6a9463f1 Dmitry Vyukov 2017-03-15  72  
6a9463f1 Dmitry Vyukov 2017-03-15  73  

:::::: The code at line 70 was first introduced by commit
:::::: 6a9463f1bb9223614d0ca81a5b237102ce81c7c1 asm-generic, x86: wrap atomic operations

:::::: TO: Dmitry Vyukov <dvyukov@google.com>
:::::: CC: Michal Hocko <mhocko@suse.com>

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