Subject: linux-next: build failure after merge of the mm tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 30 Apr 2024 10:38:11 +1000

Hi all,

After merging the mm tree, today's linux-next build (arm
multi_v7_defconfig) failed like this:

In file included from <command-line>:
mm/rmap.c: In function 'try_to_unmap_one':
include/linux/compiler_types.h:460:45: error: call to '__compiletime_assert_344' declared with attribute error: BUILD_BUG failed
  460 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |                                             ^
include/linux/compiler_types.h:441:25: note: in definition of macro '__compiletime_assert'
  441 |                         prefix ## suffix();                             \
      |                         ^~~~~~
include/linux/compiler_types.h:460:9: note: in expansion of macro '_compiletime_assert'
  460 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |         ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
   39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
      |                                     ^~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG'
   59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
      |                     ^~~~~~~~~~~~~~~~
include/linux/huge_mm.h:99:28: note: in expansion of macro 'BUILD_BUG'
   99 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
      |                            ^~~~~~~~~
include/linux/huge_mm.h:106:35: note: in expansion of macro 'HPAGE_PMD_SHIFT'
  106 | #define HPAGE_PMD_SIZE  ((1UL) << HPAGE_PMD_SHIFT)
      |                                   ^~~~~~~~~~~~~~~
include/linux/huge_mm.h:105:28: note: in expansion of macro 'HPAGE_PMD_SIZE'
  105 | #define HPAGE_PMD_MASK  (~(HPAGE_PMD_SIZE - 1))
      |                            ^~~~~~~~~~~~~~
mm/rmap.c:1651:41: note: in expansion of macro 'HPAGE_PMD_MASK'
 1651 |                 range.start = address & HPAGE_PMD_MASK;
      |                                         ^~~~~~~~~~~~~~

Caused by commit

  34d66beb14bd ("mm/rmap: integrate PMD-mapped folio splitting into pagewalk loop")

from the mm-unstable branch of the mm tree.

I have reverted that commit and the following one for today.

-- 
Cheers,
Stephen Rothwell