[PATCH 4.19 090/105] mm: Fix .data.once orphan section warning

Greg Kroah-Hartman
2022-12-05T19:22:55Z

From: Nathan Chancellor <nathan@kernel.org>

Portions of upstream commit a4055888629b ("mm/memcg: warning on !memcg
after readahead page charged") were backported as commit cfe575954ddd
("mm: add VM_WARN_ON_ONCE_PAGE() macro"). Unfortunately, the backport
did not account for the lack of commit 33def8498fdd ("treewide: Convert
macro and uses of __section(foo) to __section("foo")") in kernels prior
to 5.10, resulting in the following orphan section warnings on PowerPC
clang builds with CONFIG_DEBUG_VM=y:

powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'
powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'
powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'

This is a difference between how clang and gcc handle macro
stringification, which was resolved for the kernel by not stringifying
the argument to the __section() macro. Since that change was deemed not
suitable for the stable kernels by commit 59f89518f510 ("once: fix
section mismatch on clang builds"), do that same thing as that change
and remove the quotes from the argument to __section().

Fixes: cfe575954ddd ("mm: add VM_WARN_ON_ONCE_PAGE() macro")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/mmdebug.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -38,7 +38,7 @@ void dump_mm(const struct mm_struct *mm)
} \
} while (0)
#define VM_WARN_ON_ONCE_PAGE(cond, page) ({ \
- static bool __section(".data.once") __warned; \
+ static bool __section(.data.once) __warned; \
int __ret_warn_once = !!(cond); \
\
if (unlikely(__ret_warn_once && !__warned)) { \