From 6845d64d51cf69c096176e34864e161429bcb664 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 2 Mar 2022 12:38:18 +0100 Subject: ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y Commit 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder") removed the dummy version of return_address() that was provided for the CONFIG_ARM_UNWIND=y case, on the assumption that the removal of the kernel_text_address() call from unwind_frame() in the preceding patch made it safe to do so. However, this turns out not to be the case: Corentin reports warnings about suspicious RCU usage and other strange behavior that seems to originate in the stack unwinding that occurs in return_address(). Given that the function graph tracer (which is what these changes were enabling for CONFIG_ARM_UNWIND=y builds) does not appear to care about this distinction, let's revert return_address() to the old state. Cc: Corentin Labbe Fixes: 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder") Signed-off-by: Ard Biesheuvel Reported-by: Corentin Labbe Tested-by: Corentin Labbe Signed-off-by: Russell King (Oracle) --- arch/arm/kernel/Makefile | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/arm/kernel/Makefile') diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 5cebb8d5a1d6..56511856ff9d 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -25,7 +25,10 @@ obj-y := elf.o entry-common.o irq.o opcodes.o \ KASAN_SANITIZE_stacktrace.o := n KASAN_SANITIZE_traps.o := n -obj-y += return_address.o +ifneq ($(CONFIG_ARM_UNWIND),y) +obj-$(CONFIG_FRAME_POINTER) += return_address.o +endif + obj-$(CONFIG_ATAGS) += atags_parse.o obj-$(CONFIG_ATAGS_PROC) += atags_proc.o obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o -- cgit