On 2/1/21 7:32 PM, akpm@linux-foundation.org wrote:
> The mm-of-the-moment snapshot 2021-02-01-19-29 has been uploaded to
> 
>    https://www.ozlabs.org/~akpm/mmotm/
> 
> mmotm-readme.txt says
> 
> README for mm-of-the-moment:
> 
> https://www.ozlabs.org/~akpm/mmotm/
> 
> This is a snapshot of my -mm patch queue.  Uploaded at random hopefully
> more than once a week.
> 
> You will need quilt to apply these patches to the latest Linus release (5.x
> or 5.x-rcY).  The series file is in broken-out.tar.gz and is duplicated in
> https://ozlabs.org/~akpm/mmotm/series
> 
> The file broken-out.tar.gz contains two datestamp files: .DATE and
> .DATE-yyyy-mm-dd-hh-mm-ss.  Both contain the string yyyy-mm-dd-hh-mm-ss,
> followed by the base kernel version against which this patch series is to
> be applied.

4 of 10 i386 builds had hundreds of build errors.
Those same 4 builds had CONFIG_SPARSEMEM=y.
It may be a coincidence -- I haven't found out yet.

One of the 4 randconfig files is attached.

Here is a sampling of build errors:

../include/linux/mm.h: In function ‘is_pinnable_page’:
../include/asm-generic/memory_model.h:64:14: error: implicit declaration of function ‘page_to_section’; did you mean ‘__nr_to_section’? [-Werror=implicit-function-declaration]
  int __sec = page_to_section(__pg);   \
              ^
../include/asm-generic/memory_model.h:81:21: note: in expansion of macro ‘__page_to_pfn’
 #define page_to_pfn __page_to_pfn
                     ^~~~~~~~~~~~~
../include/linux/mmzone.h:94:32: note: in expansion of macro ‘page_to_pfn’
  get_pfnblock_flags_mask(page, page_to_pfn(page), MIGRATETYPE_MASK)
                                ^~~~~~~~~~~
../include/linux/mmzone.h:74:39: note: in expansion of macro ‘get_pageblock_migratetype’
 #  define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
                                       ^~~~~~~~~~~~~~~~~~~~~~~~~
../include/linux/mm.h:1133:41: note: in expansion of macro ‘is_migrate_cma_page’
  return !(is_zone_movable_page(page) || is_migrate_cma_page(page)) ||
                                         ^~~~~~~~~~~~~~~~~~~
In file included from ../include/linux/kallsyms.h:12:0,
                 from ../include/linux/bpf.h:21,
                 from ../include/linux/bpf-cgroup.h:5,
                 from ../include/linux/cgroup-defs.h:22,
                 from ../include/linux/cgroup.h:28,
                 from ../include/linux/memcontrol.h:13,
                 from ../include/linux/swap.h:9,
                 from ../include/linux/suspend.h:5,
                 from ../arch/x86/kernel/asm-offsets.c:13:
../include/linux/mm.h: At top level:
../include/linux/mm.h:1505:29: error: conflicting types for ‘page_to_section’
 static inline unsigned long page_to_section(const struct page *page)
                             ^~~~~~~~~~~~~~~
In file included from ../arch/x86/include/asm/page.h:76:0,
                 from ../arch/x86/include/asm/thread_info.h:12,
                 from ../include/linux/thread_info.h:56,
                 from ../arch/x86/include/asm/preempt.h:7,
                 from ../include/linux/preempt.h:78,
                 from ../include/linux/spinlock.h:51,
                 from ../include/linux/mmzone.h:8,
                 from ../include/linux/gfp.h:6,
                 from ../include/linux/slab.h:15,
                 from ../include/linux/crypto.h:20,
                 from ../arch/x86/kernel/asm-offsets.c:9:
../include/asm-generic/memory_model.h:64:14: note: previous implicit declaration of ‘page_to_section’ was here
  int __sec = page_to_section(__pg);   \
              ^
../include/asm-generic/memory_model.h:81:21: note: in expansion of macro ‘__page_to_pfn’
 #define page_to_pfn __page_to_pfn
                     ^~~~~~~~~~~~~
../include/linux/mmzone.h:94:32: note: in expansion of macro ‘page_to_pfn’
  get_pfnblock_flags_mask(page, page_to_pfn(page), MIGRATETYPE_MASK)
                                ^~~~~~~~~~~
../include/linux/mmzone.h:74:39: note: in expansion of macro ‘get_pageblock_migratetype’
 #  define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
                                       ^~~~~~~~~~~~~~~~~~~~~~~~~
../include/linux/mm.h:1133:41: note: in expansion of macro ‘is_migrate_cma_page’
  return !(is_zone_movable_page(page) || is_migrate_cma_page(page)) ||
                                         ^~~~~~~~~~~~~~~~~~~


-- 
~Randy
Reported-by: Randy Dunlap <rdunlap@infradead.org>