[PATCH 13/15] kmemleak: Keep the __init functions after initialization

[Catalin Marinas <catalin.marinas@arm.com>]

This patch adds the CONFIG_DEBUG_KEEP_INIT option which preserves the
.init.* sections after initialization. Memory leaks happening during
this phase can be more easily tracked.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
---
 include/linux/init.h |    6 ++++++
 lib/Kconfig.debug    |   12 ++++++++++++
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 68cb026..41321ad 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -40,9 +40,15 @@
 
 /* These are for everybody (although not all archs will actually
    discard it in modules) */
+#ifdef CONFIG_DEBUG_KEEP_INIT
+#define __init
+#define __initdata
+#define __initconst
+#else
 #define __init		__section(.init.text) __cold notrace
 #define __initdata	__section(.init.data)
 #define __initconst	__section(.init.rodata)
+#endif
 #define __exitdata	__section(.exit.data)
 #define __exit_call	__used __section(.exitcall.exit)
 
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1e59827..72cde77 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -313,6 +313,18 @@ config DEBUG_MEMLEAK
 	  In order to access the memleak file, debugfs needs to be
 	  mounted (usually at /sys/kernel/debug).
 
+config DEBUG_KEEP_INIT
+	bool "Do not free the __init code/data"
+	default n
+	depends on DEBUG_MEMLEAK
+	help
+	  This option moves the __init code/data out of the
+	  .init.text/.init.data sections. It is useful for identifying
+	  memory leaks happening during the kernel or modules
+	  initialization.
+
+	  If unsure, say N.
+
 config DEBUG_PREEMPT
 	bool "Debug preemptible kernel"
 	depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)