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Subject[PATCH v1] x86, kasan, ftrace: Put APIC interrupt handlers into .irqentry.text
Date
When building with CONFIG_FUNCTION_GRAPH_TRACER or CONFIG_KASAN, put the
APIC interrupt handlers into the .irqentry.text section. This is needed
because both KASAN and function graph tracer use __irqentry_text_start and
__irqentry_text_end to determine whether a function is an IRQ entry point.

Dmitry Vyukov has reported unexpected KASAN stackdepot growth
(https://github.com/google/kasan/issues/36), which had been caused by
the APIC handlers not being present in .irqentry.text.

Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
---
arch/x86/entry/entry_64.S | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 9ee0da1..966b1a8 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -601,9 +601,20 @@ apicinterrupt3 \num trace(\sym) smp_trace(\sym)
.endm
#endif

+/* Make sure APIC interrupt handlers end up in the irqentry section. */
+#ifdef defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
+#define PUSH_SECTION_IRQENTRY .pushsection .irqentry.text, "ax"
+#define POP_SECTION_IRQENTRY .popsection
+#else
+#define PUSH_SECTION_IRQENTRY
+#define POP_SECTION_IRQENTRY
+#endif
+
.macro apicinterrupt num sym do_sym
+PUSH_SECTION_IRQENTRY
apicinterrupt3 \num \sym \do_sym
trace_apicinterrupt \num \sym
+POP_SECTION_IRQENTRY
.endm

#ifdef CONFIG_SMP
--
2.8.0.rc3.226.g39d4020
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