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Rename .data.unlikely to .data..unlikely

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[ 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@mail.gmail.com/

Fixes: cb87481ee89d ("kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Masahiro Yamada 2024-11-07 01:14:40 +09:00 committed by Greg Kroah-Hartman
parent fc9af4c0cf
commit 513b1f8bae
2 changed files with 2 additions and 2 deletions
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2
include/asm-generic/vmlinux.lds.h
View File

@ -349,7 +349,7 @@
*(.data..decrypted) \
*(.ref.data) \
*(.data..shared_aligned) /* percpu related */ \
*(.data.unlikely) \
*(.data..unlikely) \
__start_once = .; \
*(.data.once) \
__end_once = .; \

2
include/linux/rcupdate.h
View File

@ -390,7 +390,7 @@ 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; \