This is a note to let you know that I've just added the patch titled
Rename .data.unlikely to .data..unlikely
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rename-.data.unlikely-to-.data.unlikely.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6746d922f37435675cadb4728cc9a248de35038f
Author: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Date: Thu Nov 7 01:14:40 2024 +0900
Rename .data.unlikely to .data..unlikely
[ Upstream commit bb43a59944f45e89aa158740b8a16ba8f0b0fa2b ]
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>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 5793aedb24c6d..cb12f164caf1e 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -347,7 +347,7 @@
*(.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 6466c2f792923..7602d1f8a9ecb 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -398,7 +398,7 @@ 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; \
