[android-common:android14-5.15 1/1] include/linux/userfaultfd_k.h:82:1: warning: control reaches end of non-void function

[android-common:android14-5.15 1/1] include/linux/userfaultfd_k.h:82:1: warning: control reaches end of non-void function

[kernel test robot]

tree:   https://android.googlesource.com/kernel/common android14-5.15
head:   f598b4e36c5884e38780f70315660738694c035d
commit: ee9964b308a6ee11d1cf5ee778dc91030f084489 [1/1] ANDROID: userfaultfd: allow SPF for UFFD_FEATURE_SIGBUS on private+anon
config: arm-randconfig-r121-20260910 (https://download.01.org/0day-ci/archive/20260913/202609130713.NuVP6RXC-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 7.5.0
sparse: v0.6.5-rc1
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260913/202609130713.NuVP6RXC-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202609130713.NuVP6RXC-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/rbtree.h:24:0,
                    from include/linux/mm_types.h:11,
                    from include/linux/mmzone.h:22,
                    from include/linux/gfp.h:6,
                    from include/linux/slab.h:15,
                    from mm/mmap.c:13:
   include/linux/userfaultfd_k.h: In function 'is_mergeable_vm_userfaultfd_ctx':
   include/linux/rcupdate.h:391:9: error: dereferencing pointer to incomplete type 'struct userfaultfd_ctx'
     typeof(*p) *_________p1 = (typeof(*p) *__force)READ_ONCE(p); \
            ^
   include/linux/rcupdate.h:501:31: note: in expansion of macro '__rcu_access_pointer'
    #define rcu_access_pointer(p) __rcu_access_pointer((p), __rcu)
                                  ^~~~~~~~~~~~~~~~~~~~
   include/linux/userfaultfd_k.h:81:9: note: in expansion of macro 'rcu_access_pointer'
     return rcu_access_pointer(vma->vm_userfaultfd_ctx.ctx) == vm_ctx.ctx;
            ^~~~~~~~~~~~~~~~~~
   In file included from include/linux/hugetlb.h:15:0,
                    from mm/mmap.c:29:
>> include/linux/userfaultfd_k.h:82:1: warning: control reaches end of non-void function [-Wreturn-type]
    }
    ^


vim +82 include/linux/userfaultfd_k.h

f619147104c8ea Axel Rasmussen   2021-05-04  58  
7d64ae3ab648a9 Axel Rasmussen   2021-06-30  59  extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
7d64ae3ab648a9 Axel Rasmussen   2021-06-30  60  				    struct vm_area_struct *dst_vma,
7d64ae3ab648a9 Axel Rasmussen   2021-06-30  61  				    unsigned long dst_addr, struct page *page,
7d64ae3ab648a9 Axel Rasmussen   2021-06-30  62  				    bool newly_allocated, bool wp_copy);
7d64ae3ab648a9 Axel Rasmussen   2021-06-30  63  
c1a4de99fada21 Andrea Arcangeli 2015-09-04  64  extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
df2cc96e77011c Mike Rapoport    2018-06-07  65  			    unsigned long src_start, unsigned long len,
a759a909d42d72 Nadav Amit       2021-09-02  66  			    atomic_t *mmap_changing, __u64 mode);
c1a4de99fada21 Andrea Arcangeli 2015-09-04  67  extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
c1a4de99fada21 Andrea Arcangeli 2015-09-04  68  			      unsigned long dst_start,
df2cc96e77011c Mike Rapoport    2018-06-07  69  			      unsigned long len,
a759a909d42d72 Nadav Amit       2021-09-02  70  			      atomic_t *mmap_changing);
f619147104c8ea Axel Rasmussen   2021-05-04  71  extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start,
a759a909d42d72 Nadav Amit       2021-09-02  72  			      unsigned long len, atomic_t *mmap_changing);
ffd05793963a44 Shaohua Li       2020-04-06  73  extern int mwriteprotect_range(struct mm_struct *dst_mm,
ffd05793963a44 Shaohua Li       2020-04-06  74  			       unsigned long start, unsigned long len,
a759a909d42d72 Nadav Amit       2021-09-02  75  			       bool enable_wp, atomic_t *mmap_changing);
c1a4de99fada21 Andrea Arcangeli 2015-09-04  76  
932b18e0aec65a Andrea Arcangeli 2015-09-04  77  /* mm helpers */
932b18e0aec65a Andrea Arcangeli 2015-09-04  78  static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
932b18e0aec65a Andrea Arcangeli 2015-09-04  79  					struct vm_userfaultfd_ctx vm_ctx)
932b18e0aec65a Andrea Arcangeli 2015-09-04  80  {
ee9964b308a6ee Lokesh Gidra     2024-01-16  81  	return rcu_access_pointer(vma->vm_userfaultfd_ctx.ctx) == vm_ctx.ctx;
932b18e0aec65a Andrea Arcangeli 2015-09-04 @82  }
932b18e0aec65a Andrea Arcangeli 2015-09-04  83  

:::::: The code at line 82 was first introduced by commit
:::::: 932b18e0aec65acb089f4bd8761ee85e70f8eb6a userfaultfd: linux/userfaultfd_k.h

:::::: TO: Andrea Arcangeli <aarcange@redhat.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

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