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

From: Stephen Rothwell <[email-masked]>
Date: Tue, 26 Oct 2021 10:25:36 +1100

Hi all,

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

In file included from <command-line>:
arch/arm/mm/mmu.c: In function 'early_fixmap_init':
include/linux/compiler_types.h:328:38: error: call to '__compiletime_assert_295' declared with attribute error: BUILD_BUG_ON failed: (__fix_to_virt(__end_of_fixmap_region) >> PMD_SHIFT) != FIXADDR_TOP >> PMD_SHIFT
  328 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |                                      ^
include/linux/compiler_types.h:309:4: note: in definition of macro '__compiletime_assert'
  309 |    prefix ## suffix();    \
      |    ^~~~~~
include/linux/compiler_types.h:328:2: note: in expansion of macro '_compiletime_assert'
  328 |  _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:50:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
   50 |  BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
      |  ^~~~~~~~~~~~~~~~
arch/arm/mm/mmu.c:372:2: note: in expansion of macro 'BUILD_BUG_ON'
  372 |  BUILD_BUG_ON((__fix_to_virt(__end_of_fixmap_region) >> PMD_SHIFT)
      |  ^~~~~~~~~~~~

Exposed by commit

  9b89a073e1ca ("ARM: 9149/1: add BUILD_BUG_ON to check if fixmap range spans multiple pmds")

I have no idea why that BUILD_BUG_ON hits, so I have just reverted that
commit for today.

-- 
Cheers,
Stephen Rothwell