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From:   Arvind Sankar <nivedita@alum.mit.edu>
Date:   Mon, 23 Sep 2019 13:17:54 -0400
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Arvind Sankar <nivedita@alum.mit.edu>,
        LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>
Subject: [PATCH] x86/purgatory: Add $(DISABLE_STACKLEAK_PLUGIN)
Message-ID: <20190923171753.GA2252517@rani.riverdale.lan>
References: <20190922173241.GA44503@rani.riverdale.lan>
 <CAKwvOd=X9+uxQSzKad8B-Lw=ZarBT+SfNpBm_TE0k+DeJZmrsw@mail.gmail.com>
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Since commit b059f801a937 ("x86/purgatory: Use CFLAGS_REMOVE rather than
reset KBUILD_CFLAGS") kexec breaks is GCC_PLUGIN_STACKLEAK is enabled, as
the purgatory contains undefined references to stackleak_track_stack.
Attempting to load a kexec kernel results in:
	kexec: Undefined symbol: stackleak_track_stack
	kexec-bzImage64: Loading purgatory failed

Fix this by disabling the stackleak plugin for purgatory.

Fixes: b059f801a937 ("x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS")
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
 arch/x86/purgatory/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 527749066d31..fb4ee5444379 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -25,6 +25,7 @@ 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
-- 
2.21.0