Unverified Commit 573ad421 authored by Nathan Chancellor's avatar Nathan Chancellor
Browse files

objtool: Drop noinstr hack for KCSAN_WEAK_MEMORY 



Now that the minimum supported version of LLVM for building the kernel
has been bumped to 15.0.0, __no_kcsan will always ensure that the thread
sanitizer functions are not generated, so remove the check for tsan
functions in is_profiling_func() and the always true depends and
unnecessary select lines in KCSAN_WEAK_MEMORY.

Acked-by: default avatarMarco Elver <elver@google.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infraded.org>
Reviewed-by: default avatarKees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250821-bump-min-llvm-ver-15-v2-11-635f3294e5f0@kernel.org


Signed-off-by: default avatarNathan Chancellor <nathan@kernel.org>
parent a817de20

lib/Kconfig.kcsan

+0 −6
Original line number Diff line number Diff line
@@ -185,12 +185,6 @@ config KCSAN_WEAK_MEMORY 
	bool "Enable weak memory modeling to detect missing memory barriers"

	default y

	depends on KCSAN_STRICT

	# We can either let objtool nop __tsan_func_{entry,exit}() and builtin

	# atomics instrumentation in .noinstr.text, or use a compiler that can

	# implement __no_kcsan to really remove all instrumentation.

	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \

		   CC_IS_GCC || CLANG_VERSION >= 140000

	select OBJTOOL if HAVE_NOINSTR_HACK

	help

	  Enable support for modeling a subset of weak memory, which allows

	  detecting a subset of data races due to missing memory barriers.

tools/objtool/check.c

+0 −10
Original line number Diff line number Diff line
@@ -2453,16 +2453,6 @@ static bool is_profiling_func(const char *name) 
	if (!strncmp(name, "__sanitizer_cov_", 16))

		return true;



	/*

	 * Some compilers currently do not remove __tsan_func_entry/exit nor

	 * __tsan_atomic_signal_fence (used for barrier instrumentation) with

	 * the __no_sanitize_thread attribute, remove them. Once the kernel's

	 * minimum Clang version is 14.0, this can be removed.

	 */

	if (!strncmp(name, "__tsan_func_", 12) ||

	    !strcmp(name, "__tsan_atomic_signal_fence"))

		return true;



	return false;

}