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* FAILED: patch "[PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset" failed to apply to 4.4-stable tree
@ 2019-08-13 18:40 gregkh
  0 siblings, 0 replies; only message in thread
From: gregkh @ 2019-08-13 18:40 UTC (permalink / raw)
  To: ndesaulniers, peterz, tglx, vaibhavrustagi; +Cc: stable

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <>.


greg k-h

------------------ original commit in Linus's tree ------------------

From b059f801a937d164e03b33c1848bb3dca67c0b04 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <>
Date: Wed, 7 Aug 2019 15:15:33 -0700
Subject: [PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset

KBUILD_CFLAGS is very carefully built up in the top level Makefile,
particularly when cross compiling or using different build tools.
Resetting KBUILD_CFLAGS via := assignment is an antipattern.

The comment above the reset mentions that -pg is problematic.  Other
Makefiles use `CFLAGS_REMOVE_file.o = $(CC_FLAGS_FTRACE)` when
CONFIG_FUNCTION_TRACER is set. Prefer that pattern to wiping out all of
the important KBUILD_CFLAGS then manually having to re-add them. Seems
also that __stack_chk_fail references are generated when using

Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality")
Reported-by: Vaibhav Rustagi <>
Suggested-by: Peter Zijlstra <>
Suggested-by: Thomas Gleixner <>
Signed-off-by: Nick Desaulniers <>
Signed-off-by: Thomas Gleixner <>
Tested-by: Vaibhav Rustagi <>

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 91ef244026d2..8901a1f89cf5 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -20,11 +20,34 @@ KCOV_INSTRUMENT := n
 # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
 # in turn leaves some undefined symbols like __fentry__ in purgatory and not
-# sure how to relocate those. Like kexec-tools, use custom flags.
-KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large
-KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
+# sure how to relocate those.
+CFLAGS_REMOVE_kexec-purgatory.o	+= $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_sha256.o		+= -fstack-protector
+CFLAGS_REMOVE_purgatory.o	+= -fstack-protector
+CFLAGS_REMOVE_string.o		+= -fstack-protector
+CFLAGS_REMOVE_kexec-purgatory.o	+= -fstack-protector
+CFLAGS_REMOVE_sha256.o		+= -fstack-protector-strong
+CFLAGS_REMOVE_purgatory.o	+= -fstack-protector-strong
+CFLAGS_REMOVE_string.o		+= -fstack-protector-strong
+CFLAGS_REMOVE_kexec-purgatory.o	+= -fstack-protector-strong
+CFLAGS_REMOVE_kexec-purgatory.o	+= $(RETPOLINE_CFLAGS)
 		$(call if_changed,ld)

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2019-08-13 18:40 FAILED: patch "[PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset" failed to apply to 4.4-stable tree gregkh

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