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Date:   Mon, 23 Sep 2019 17:52:37 -0000
From:   "tip-bot2 for Arvind Sankar" <tip-bot2@linutronix.de>
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To:     linux-tip-commits@vger.kernel.org
Subject: [tip: x86/urgent] x86/purgatory: Disable the stackleak GCC plugin for
 the purgatory
Cc:     Arvind Sankar <nivedita@alum.mit.edu>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>, linux-kernel@vger.kernel.org
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The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     ca14c996afe7228ff9b480cf225211cc17212688
Gitweb:        https://git.kernel.org/tip/ca14c996afe7228ff9b480cf225211cc17212688
Author:        Arvind Sankar <nivedita@alum.mit.edu>
AuthorDate:    Mon, 23 Sep 2019 13:17:54 -04:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 23 Sep 2019 19:48:02 +02:00

x86/purgatory: Disable the stackleak GCC plugin for the purgatory

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>
---
 arch/x86/purgatory/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 10fb42d..b81b517 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