The kernel compiled with multi_v7_defconfig + CONFIG_KASAN=y + CONFIG_KASAN_INLINE=y does not boot. I do not think KASAN is the direct reason of the boot failure. CONFIG_KASAN_INLINE is just one example configuration that grows the image size significantly and makes a big distance between function callers and callees. I see some veneers for __get_user_* in the bad kernel image. I am not perfectly clear, but __get_user_* may not work with veneers for some reasons. If I move the link order of arch/arm/lib/getuser.S, the veneers are gone, and the kernel gets working again. I do not see a good reason that $(mmu-y) must be added to lib-y because all the code in $(mmu-y) is mandatory. Add it to obj-y to move the code to lower address. [1] multi_v7_defconfig (works) $ arm-linux-gnueabihf-nm vmlinux | grep __get_user_1 c072a450 T __get_user_1 c17ea033 r __kstrtab___get_user_1 c18119fe r __kstrtabns___get_user_1 c17c4878 r __ksymtab___get_user_1 [2] multi_v7_defconfig + CONFIG_KASAN_INLINE (does not work) $ arm-linux-gnueabihf-nm vmlinux | grep __get_user_1 c341ec2c T __get_user_1 c06e3580 t ____get_user_1_veneer c0adc6c0 t ____get_user_1_veneer c12cf054 t ____get_user_1_veneer c43f42cc r __kstrtab___get_user_1 c441c128 r __kstrtabns___get_user_1 c43cead8 r __ksymtab___get_user_1 [3] multi_v7_defconfig + CONFIG_KASAN_INLINE + this patch (works) $ arm-linux-gnueabihf-nm vmlinux | grep __get_user_1 c10975b0 T __get_user_1 c43f42cc r __kstrtab___get_user_1 c441c128 r __kstrtabns___get_user_1 c43cead8 r __ksymtab___get_user_1 Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> --- arch/arm/lib/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index 650404be6768..4d092ef87a1d 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -28,7 +28,7 @@ endif # using lib_ here won't override already available weak symbols obj-$(CONFIG_UACCESS_WITH_MEMCPY) += uaccess_with_memcpy.o -lib-$(CONFIG_MMU) += $(mmu-y) +obj-$(CONFIG_MMU) += $(mmu-y) ifeq ($(CONFIG_CPU_32v3),y) lib-y += io-readsw-armv3.o io-writesw-armv3.o -- 2.39.2
