[PATCH AUTOSEL 5.3 31/71] x86/purgatory: Disable the stackleak GCC plugin for the purgatory

Sasha Levin
2019-10-01T17:02:12Z

From: Arvind Sankar <nivedita@alum.mit.edu>

[ Upstream commit ca14c996afe7228ff9b480cf225211cc17212688 ]

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: Sasha Levin <sashal@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 10fb42da0007e..b81b5172cf994 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
--
2.20.1