Rename .data.unlikely to .data..unlikely

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>

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index c995474e4c6499ecd66b5ec192ee2cce8fc87162..3c9dc1fd094d5fb3a39c8d14acd77709ec65ef67 100644 (file)
--- 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 58d84c59f3ddae9bc242c16aa7e8ee6678d56ecd..48e5c03df1dd83c246a61d0fcc8aa638adcd7654 100644 (file)
--- 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;                                \