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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 19:03:04 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-09-30 10:18:35 +0200
commita521e942bd9b903935d4c79993bf6d0b6d5154c7 (patch)
tree8a00d371534e40e6e8563fecc512ee4267bd673d /Makefile
parent3da2a4cb6e909dd45be3009379f0d29b9a9e369d (diff)
downloadlinux-linaro-stable-a521e942bd9b903935d4c79993bf6d0b6d5154c7.tar.gz
Disable "frame-address" warning
commit 124a3d88fa20e1869fc229d7d8c740cc81944264 upstream. Newer versions of gcc warn about the use of __builtin_return_address() with a non-zero argument when "-Wall" is specified: kernel/trace/trace_irqsoff.c: In function ‘stop_critical_timings’: kernel/trace/trace_irqsoff.c:433:86: warning: calling ‘__builtin_return_address’ with a nonzero argument is unsafe [-Wframe-address] stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); [ .. repeats a few times for other similar cases .. ] It is true that a non-zero argument is somewhat dangerous, and we do not actually have very many uses of that in the kernel - but the ftrace code does use it, and as Stephen Rostedt says: "We are well aware of the danger of using __builtin_return_address() of > 0. In fact that's part of the reason for having the "thunk" code in x86 (See arch/x86/entry/thunk_{64,32}.S). [..] it adds extra frames when tracking irqs off sections, to prevent __builtin_return_address() from accessing bad areas. In fact the thunk_32.S states: 'Trampoline to trace irqs off. (otherwise CALLER_ADDR1 might crash)'." For now, __builtin_return_address() with a non-zero argument is the best we can do, and the warning is not helpful and can end up making people miss other warnings for real problems. So disable the frame-address warning on compilers that need it. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile1
1 files changed, 1 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index 734579371fad..39250a7bd6a5 100644
--- a/Makefile
+++ b/Makefile
@@ -617,6 +617,7 @@ include arch/$(SRCARCH)/Makefile
KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,)
KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,)
+KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,)
ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
KBUILD_CFLAGS += -Os