Commit 7ccaba5314ca ("consolidate WARN_...ONCE() static variables")
was intended to collect all .data.unlikely sections into one chunk.
However, this has not worked when CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
or CONFIG_LTO_CLANG is enabled, because .data.unlikely matches the
.data.[0-9a-zA-Z_]* pattern in the DATA_MAIN macro.
Commit cb87481ee89d ("kbuild: linker script do not match C names unless
LD_DEAD_CODE_DATA_ELIMINATION is configured") was introduced to suppress
the issue for the default CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=n case,
providing a minimal fix for stable backporting. We were aware this did
not address the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. The
plan was to apply correct fixes and then revert cb87481ee89d. [1]
Seven years have passed since then, yet the #ifdef workaround remains in
place.
Using a ".." separator in the section name fixes the issue for
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION and CONFIG_LTO_CLANG.
[1]: https://lore.kernel.org/linux-kbuild/CAK7LNASck6BfdLnESxXUeECYL26yUDm0cwRZuM4gmaWUkxjL5g@xxxxxxxxxxxxxx/
Fixes: cb87481ee89d ("kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured")
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---
include/asm-generic/vmlinux.lds.h | 2 +-
include/linux/rcupdate.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index c995474e4c64..3c9dc1fd094d 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -357,7 +357,7 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
*(.data..decrypted) \
*(.ref.data) \
*(.data..shared_aligned) /* percpu related */ \
- *(.data.unlikely) \
+ *(.data..unlikely) \
__start_once = .; \
*(.data.once) \
__end_once = .; \
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 58d84c59f3dd..48e5c03df1dd 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -401,7 +401,7 @@ static inline int debug_lockdep_rcu_enabled(void)
*/
#define RCU_LOCKDEP_WARN(c, s) \
do { \
- static bool __section(".data.unlikely") __warned; \
+ static bool __section(".data..unlikely") __warned; \
if (debug_lockdep_rcu_enabled() && (c) && \
debug_lockdep_rcu_enabled() && !__warned) { \
__warned = true; \
--
2.43.0
