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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, arnd@arndb.de, aslan@fb.com,
	bhe@redhat.com, david@redhat.com, faiyazm@codeaurora.org,
	linux-mm@kvack.org, mm-commits@vger.kernel.org,
	nathan@kernel.org, ndesaulniers@google.com, rppt@linux.ibm.com,
	torvalds@linux-foundation.org, tsbogend@alpha.franken.de
Subject: [patch 01/29] memblock: fix section mismatch warning
Date: Fri, 12 Mar 2021 21:07:01 -0800	[thread overview]
Message-ID: <20210313050701.ETLGdrycV%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210312210632.9b7d62973d72a56fb13c7a03@linux-foundation.org>

From: Arnd Bergmann <arnd@arndb.de>
Subject: memblock: fix section mismatch warning

The inlining logic in clang-13 is rewritten to often not inline some
functions that were inlined by all earlier compilers.

In case of the memblock interfaces, this exposed a harmless bug of a
missing __init annotation:

WARNING: modpost: vmlinux.o(.text+0x507c0a): Section mismatch in reference from the function memblock_bottom_up() to the variable .meminit.data:memblock
The function memblock_bottom_up() references
the variable __meminitdata memblock.
This is often because memblock_bottom_up lacks a __meminitdata
annotation or the annotation of memblock is wrong.

Interestingly, these annotations were present originally, but got removed
with the explanation that the __init annotation prevents the function from
getting inlined.  I checked this again and found that while this is the
case with clang, gcc (version 7 through 10, did not test others) does
inline the functions regardless.

As the previous change was apparently intended to help the clang builds,
reverting it to help the newer clang versions seems appropriate as well. 
gcc builds don't seem to care either way.

Link: https://lkml.kernel.org/r/20210225133808.2188581-1-arnd@kernel.org
Fixes: 5bdba520c1b3 ("mm: memblock: drop __init from memblock functions to make it inline")
Reference: 2cfb3665e864 ("include/linux/memblock.h: add __init to memblock_set_bottom_up()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Faiyaz Mohammed <faiyazm@codeaurora.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Aslan Bakirov <aslan@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/memblock.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/include/linux/memblock.h~memblock-fix-section-mismatch-warning
+++ a/include/linux/memblock.h
@@ -460,7 +460,7 @@ static inline void memblock_free_late(ph
 /*
  * Set the allocation direction to bottom-up or top-down.
  */
-static inline void memblock_set_bottom_up(bool enable)
+static inline __init void memblock_set_bottom_up(bool enable)
 {
 	memblock.bottom_up = enable;
 }
@@ -470,7 +470,7 @@ static inline void memblock_set_bottom_u
  * if this is true, that said, memblock will allocate memory
  * in bottom-up direction.
  */
-static inline bool memblock_bottom_up(void)
+static inline __init bool memblock_bottom_up(void)
 {
 	return memblock.bottom_up;
 }
_

  reply	other threads:[~2021-03-13  5:07 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-13  5:06 incoming Andrew Morton
2021-03-13  5:07 ` Andrew Morton [this message]
2021-03-13  5:07 ` [patch 02/29] stop_machine: mark helpers __always_inline Andrew Morton
2021-03-13  5:07 ` [patch 03/29] init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM Andrew Morton
2021-03-13  5:07 ` [patch 04/29] mm/page_alloc.c: refactor initialization of struct page for holes in memory layout Andrew Morton
2021-03-13  5:07 ` [patch 05/29] mm/fork: clear PASID for new mm Andrew Morton
2021-03-13  5:07 ` [patch 06/29] hugetlb: dedup the code to add a new file_region Andrew Morton
2021-03-13  5:07 ` [patch 07/29] hugetlb: break earlier in add_reservation_in_range() when we can Andrew Morton
2021-03-13  5:07 ` [patch 08/29] mm: introduce page_needs_cow_for_dma() for deciding whether cow Andrew Morton
2021-03-13  5:07 ` [patch 09/29] mm: use is_cow_mapping() across tree where proper Andrew Morton
2021-03-13  5:07 ` [patch 10/29] hugetlb: do early cow when page pinned on src mm Andrew Morton
2021-03-13  5:07 ` [patch 11/29] mm/highmem.c: fix zero_user_segments() with start > end Andrew Morton
2021-03-13  5:07 ` [patch 12/29] binfmt_misc: fix possible deadlock in bm_register_write Andrew Morton
2021-03-13  5:07 ` [patch 13/29] MAINTAINERS: exclude uapi directories in API/ABI section Andrew Morton
2021-03-13  5:07 ` [patch 14/29] linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP* Andrew Morton
2021-03-13  5:07 ` [patch 15/29] kfence: fix printk format for ptrdiff_t Andrew Morton
2021-03-13  5:07 ` [patch 16/29] kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations Andrew Morton
2021-03-13  5:08 ` [patch 17/29] kfence: fix reports if constant function prefixes exist Andrew Morton
2021-03-13  5:08 ` [patch 18/29] include/linux/sched/mm.h: use rcu_dereference in in_vfork() Andrew Morton
2021-03-13  5:08 ` [patch 19/29] mm/madvise: replace ptrace attach requirement for process_madvise Andrew Morton
2021-03-13  5:08 ` [patch 20/29] kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC Andrew Morton
2021-03-13  5:08 ` [patch 21/29] kasan: fix KASAN_STACK dependency for HW_TAGS Andrew Morton
2021-03-13  5:08 ` [patch 22/29] mm/userfaultfd: fix memory corruption due to writeprotect Andrew Morton
2021-03-13  5:08 ` [patch 23/29] mm, hwpoison: do not lock page again when me_huge_page() successfully recovers Andrew Morton
2021-03-13 19:23   ` Linus Torvalds
2021-03-13 19:23     ` Linus Torvalds
2021-03-14  6:36     ` HORIGUCHI NAOYA(堀口　直也)
2021-03-13  5:08 ` [patch 24/29] ia64: fix ia64_syscall_get_set_arguments() for break-based syscalls Andrew Morton
2021-03-13  5:08 ` [patch 25/29] ia64: fix ptrace(PTRACE_SYSCALL_INFO_EXIT) sign Andrew Morton
2021-03-13  5:08 ` [patch 26/29] mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument Andrew Morton
2021-03-13  5:08 ` [patch 27/29] mm/memcg: set memcg when splitting page Andrew Morton
2021-03-13  5:08 ` [patch 28/29] zram: fix return value on writeback_store Andrew Morton
2021-03-13  5:08 ` [patch 29/29] zram: fix broken page writeback Andrew Morton

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