path: root/Makefile
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authorLinus Torvalds <>2016-07-27 19:03:04 -0700
committerLinus Torvalds <>2016-07-27 19:03:04 -0700
commit124a3d88fa20e1869fc229d7d8c740cc81944264 (patch)
tree50f90c10a4d2626f371e7dab332d3dcc7bb32b34 /Makefile
parent8448cefe499a45222430ebbcabcd9e26369895c3 (diff)
Disable "frame-address" warning
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 <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'Makefile')
1 files changed, 1 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index d384848478b9..393b6159ae92 100644
--- a/Makefile
+++ b/Makefile
@@ -620,6 +620,7 @@ 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,)