On Thu, Aug 06, 2015 at 05:48:54PM +0800, kbuild test robot wrote:
> tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head: c6b169e6ffb962068153bd92b0c4ecbd731a122f
> commit: cbba4e22584984bffccd07e0801fd2b8ec1ecf5f [6252/6518] Move /proc/kpageidle to /sys/kernel/mm/page_idle/bitmap
> reproduce:
> # apt-get install sparse
> git checkout cbba4e22584984bffccd07e0801fd2b8ec1ecf5f
> make ARCH=x86_64 allmodconfig
> make C=1 CF=-D__CHECK_ENDIAN__
>
>
> sparse warnings: (new ones prefixed by >>)
>
> >> include/linux/mmu_notifier.h:247:19: sparse: context imbalance in 'page_idle_clear_pte_refs_one' - unexpected unlock
>
> vim +/page_idle_clear_pte_refs_one +247 include/linux/mmu_notifier.h
>
> cddb8a5c Andrea Arcangeli 2008-07-28 231
> cddb8a5c Andrea Arcangeli 2008-07-28 232 static inline void mmu_notifier_release(struct mm_struct *mm)
> cddb8a5c Andrea Arcangeli 2008-07-28 233 {
> cddb8a5c Andrea Arcangeli 2008-07-28 234 if (mm_has_notifiers(mm))
> cddb8a5c Andrea Arcangeli 2008-07-28 235 __mmu_notifier_release(mm);
> cddb8a5c Andrea Arcangeli 2008-07-28 236 }
> cddb8a5c Andrea Arcangeli 2008-07-28 237
> cddb8a5c Andrea Arcangeli 2008-07-28 238 static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
> 57128468 Andres Lagar-Cavilla 2014-09-22 239 unsigned long start,
> 57128468 Andres Lagar-Cavilla 2014-09-22 240 unsigned long end)
> cddb8a5c Andrea Arcangeli 2008-07-28 241 {
> cddb8a5c Andrea Arcangeli 2008-07-28 242 if (mm_has_notifiers(mm))
> 57128468 Andres Lagar-Cavilla 2014-09-22 243 return __mmu_notifier_clear_flush_young(mm, start, end);
> cddb8a5c Andrea Arcangeli 2008-07-28 244 return 0;
> cddb8a5c Andrea Arcangeli 2008-07-28 245 }
> cddb8a5c Andrea Arcangeli 2008-07-28 246
> 632116f6 Vladimir Davydov 2015-08-06 @247 static inline int mmu_notifier_clear_young(struct mm_struct *mm,
> 632116f6 Vladimir Davydov 2015-08-06 248 unsigned long start,
> 632116f6 Vladimir Davydov 2015-08-06 249 unsigned long end)
> 632116f6 Vladimir Davydov 2015-08-06 250 {
> 632116f6 Vladimir Davydov 2015-08-06 251 if (mm_has_notifiers(mm))
> 632116f6 Vladimir Davydov 2015-08-06 252 return __mmu_notifier_clear_young(mm, start, end);
> 632116f6 Vladimir Davydov 2015-08-06 253 return 0;
> 632116f6 Vladimir Davydov 2015-08-06 254 }
> 632116f6 Vladimir Davydov 2015-08-06 255
False-positive as I explained to the similar warning for
kpageilde_clear_pte_refs_one:
http://www.spinics.net/lists/linux-mm/msg92053.html
It is caused by page_check_address, which is not annotated as acquiring
a ptl lock.
Thanks,
Vladimir
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