release/5.2.22/x86-purgatory-Disable-the-stackleak-GCC-plugin-for-t.patch

From 2f1c6a4a8bb7501be85ca543ecc8806e20da7f0f Mon Sep 17 00:00:00 2001
From: Arvind Sankar <nivedita@alum.mit.edu>
Date: Mon, 23 Sep 2019 13:17:54 -0400
Subject: [PATCH] x86/purgatory: Disable the stackleak GCC plugin for the
 purgatory

commit ca14c996afe7228ff9b480cf225211cc17212688 upstream.

Since commit:

  b059f801a937 ("x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS")

kexec breaks if GCC_PLUGIN_STACKLEAK=y is enabled, as the purgatory
contains undefined references to stackleak_track_stack.

Attempting to load a kexec kernel results in this failure:

  kexec: Undefined symbol: stackleak_track_stack
  kexec-bzImage64: Loading purgatory failed

Fix this by disabling the stackleak plugin for the purgatory.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: b059f801a937 ("x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS")
Link: https://lkml.kernel.org/r/20190923171753.GA2252517@rani.riverdale.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 10fb42da0007..b81b5172cf99 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -23,6 +23,7 @@ KCOV_INSTRUMENT := n
 
 PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
 PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
+PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN)
 
 # 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
-- 
2.7.4