[PATCH] kbuild, sparseirq: work around GCC bug with __weak aliases

[Ingo Molnar]

Impact: fix panic on null pointer with sparseirq

Certain versions of GCC inline the weak global functions.
Work it around by marking __weak functions as noinline.

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
 include/linux/compiler-gcc.h |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 5c8351b..1ad72e6 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -41,11 +41,17 @@
 
 #define __deprecated			__attribute__((deprecated))
 #define __packed			__attribute__((packed))
-#define __weak				__attribute__((weak))
 #define __naked				__attribute__((naked))
 #define __noreturn			__attribute__((noreturn))
 
 /*
+ * Mark weak aliases also noinline, because some GCC versions
+ * incorrectly inline weak aliases (even when a non-weak variant
+ * is there) and thus cause crashes:
+ */
+#define __weak				__attribute__((weak)) noinline
+
+/*
  * From the GCC manual:
  *
  * Many functions have no effects except the return value and their
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