We currently don't instrument cmpxchg_double() and
cmpxchg_double_local() due to compilation issues reported in the past,
which are supposedly related to GCC bug 72873 [1], reported when GCC 7
was not yet released. This bug only applies to x86-64, and not other
architectures.
While the test case for GCC bug 72873 triggers issues with released
versions of GCC, the instrumented kernel code compiles fine for all
configurations I have tried, and it is unclear how the two cases
are/were related.
As we can't reproduce the kernel build failures, let's instrument
cmpxchg_double*() again. We can revisit the issue if build failures
reappear.
Signed-off-by: Mark Rutland <mark.rutl...@arm.com>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Boqun Feng <boqun.f...@gmail.com>
Cc: Dmitry Vyukov <dvyu...@google.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Will Deacon <will.dea...@arm.com>
---
include/asm-generic/atomic-instrumented.h | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/include/asm-generic/atomic-instrumented.h
b/include/asm-generic/atomic-instrumented.h
index 53481b6eacdf..0d4b1d3dbc1e 100644
--- a/include/asm-generic/atomic-instrumented.h
+++ b/include/asm-generic/atomic-instrumented.h
@@ -450,23 +450,18 @@ static __always_inline bool atomic64_add_negative(s64 i,
atomic64_t *v)
arch_cmpxchg64_local(__ai_ptr, (old), (new)); \
})
-/*
- * Originally we had the following code here:
- * __typeof__(p1) ____p1 = (p1);
- * kasan_check_write(____p1, 2 * sizeof(*____p1));
- * arch_cmpxchg_double(____p1, (p2), (o1), (o2), (n1), (n2));
- * But it leads to compilation failures (see gcc issue 72873).
- * So for now it's left non-instrumented.
- * There are few callers of cmpxchg_double(), so it's not critical.
- */
#define cmpxchg_double(p1, p2, o1, o2, n1, n2) \
({ \
- arch_cmpxchg_double((p1), (p2), (o1), (o2), (n1), (n2)); \
+ typeof(p1) __ai_p1 = (p1); \
+ kasan_check_write(__ai_p1, 2 * sizeof(*__ai_p1)); \
+ arch_cmpxchg_double(__ai_p1, (p2), (o1), (o2), (n1), (n2)); \
})
-#define cmpxchg_double_local(p1, p2, o1, o2, n1, n2) \
-({ \
- arch_cmpxchg_double_local((p1), (p2), (o1), (o2), (n1), (n2)); \
+#define cmpxchg_double_local(p1, p2, o1, o2, n1, n2)
\
+({
\
+ typeof(p1) __ai_p1 = (p1);
\
+ kasan_check_write(__ai_p1, 2 * sizeof(*__ai_p1));
\
+ arch_cmpxchg_double_local(__ai_p1, (p2), (o1), (o2), (n1), (n2));
\
})
#endif /* _LINUX_ATOMIC_INSTRUMENTED_H */
--
2.11.0
