Thread (1 message) 1 message, 1 author, 2021-09-13

Re: [PATCH] memblock: fix a section mismatch when a function doesn't get inlined

From: Mike Rapoport <rppt@kernel.org>
Date: 2021-09-13 06:40:06
Subsystem: memblock and memory management initialization, memory management, the rest · Maintainers: Mike Rapoport, Andrew Morton, Linus Torvalds

Hi Adam,

On Sun, Sep 12, 2021 at 10:41:11PM +0200, Adam Borowski wrote:
WARNING: modpost: vmlinux.o(.text.unlikely+0xab6): Section mismatch in
    reference from the function memblock_phys_alloc() to the function
    .init.text:memblock_phys_alloc_range()
The function memblock_phys_alloc() references
the function __init memblock_phys_alloc_range().
This is often because memblock_phys_alloc lacks a __init
annotation or the annotation of memblock_phys_alloc_range is wrong.
There is a bunch of other wrappers in include/linux/memblock.h that
most probably would cause the same warning.

Can add the patch below and build the kernel with the config that prevents
inlining of memblock_phys_alloc to see what the compiler thinks about other
wrappers? I believe they all would produce the same warning.
diff --git a/mm/memblock.c b/mm/memblock.c
index 28a813d9e955..6351c5754bb0 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -2089,6 +2089,32 @@ void __init memblock_free_all(void)
 	totalram_pages_add(pages);
 }
 
+void __init memblock_test_inlining(void)
+{
+	void *addr;
+
+	addr = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
+	if (!addr)
+		return;
+	memblock_free(__pa(addr), PAGE_SIZE);
+
+	addr = memblock_alloc_from(PAGE_SIZE, PAGE_SIZE,
+				   MEMBLOCK_ALLOC_ACCESSIBLE);
+	if (!addr)
+		return;
+	memblock_free(__pa(addr), PAGE_SIZE);
+
+	addr = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
+	if (!addr)
+		return;
+	memblock_free(__pa(addr), PAGE_SIZE);
+
+	addr = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, NUMA_NO_NODE);
+	if (!addr)
+		return;
+	memblock_free(__pa(addr), PAGE_SIZE);
+}
+
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
 
 static int memblock_debug_show(struct seq_file *m, void *private)
quoted hunk
Simplest way is to just ensure it is inlined.

Signed-off-by: Adam Borowski <redacted>
---
 Found when running riscv64 randconfigs, but doesn't appear to be arch
 specific.

 include/linux/memblock.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index b066024c62e3..dfdd7c50c27d 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -387,8 +387,8 @@ phys_addr_t memblock_alloc_range_nid(phys_addr_t size,
 				      phys_addr_t end, int nid, bool exact_nid);
 phys_addr_t memblock_phys_alloc_try_nid(phys_addr_t size, phys_addr_t align, int nid);
 
-static inline phys_addr_t memblock_phys_alloc(phys_addr_t size,
-					      phys_addr_t align)
+static __always_inline phys_addr_t memblock_phys_alloc(phys_addr_t size,
+						       phys_addr_t align)
 {
 	return memblock_phys_alloc_range(size, align, 0,
 					 MEMBLOCK_ALLOC_ACCESSIBLE);
-- 
2.33.0
-- 
Sincerely yours,
Mike.
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