From cf8016408d880afe9c5dc495af40dc2932874e77 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Thu, 22 Dec 2022 22:57:47 +0000 Subject: [PATCH] cfi: Fix CFI failure with KASAN When CFI_CLANG and KASAN are both enabled, LLVM doesn't generate a CFI type hash for asan.module_ctor functions in translation units where CFI is disabled, which leads to a CFI failure during boot when do_ctors calls the affected constructors: CFI failure at do_basic_setup+0x64/0x90 (target: asan.module_ctor+0x0/0x28; expected type: 0xa540670c) Specifically, this happens because CFI is disabled for kernel/cfi.c. There's no reason to keep CFI disabled here anymore, so fix the failure by not filtering out CC_FLAGS_CFI for the file. Note that https://reviews.llvm.org/rG3b14862f0a96 fixed the issue where LLVM didn't emit CFI type hashes for any sanitizer constructors, but now type hashes are emitted correctly for TUs that use CFI. Link: https://github.com/ClangBuiltLinux/linux/issues/1742 Fixes: 89245600941e ("cfi: Switch to -fsanitize=kcfi") Reported-by: Mark Rutland Signed-off-by: Sami Tolvanen Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221222225747.3538676-1-samitolvanen@google.com --- kernel/Makefile | 3 --- 1 file changed, 3 deletions(-) diff --git a/kernel/Makefile b/kernel/Makefile index d754e0be1176..ebc692242b68 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -41,9 +41,6 @@ UBSAN_SANITIZE_kcov.o := n KMSAN_SANITIZE_kcov.o := n CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector -# Don't instrument error handlers -CFLAGS_REMOVE_cfi.o := $(CC_FLAGS_CFI) - obj-y += sched/ obj-y += locking/ obj-y += power/