This patch was developed in house for Bug 21658934. Python PyObject_Free()
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implementation relies on being able to read memory that might not belong to
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the current buffer. When ADIHEAP is enabled, this is detected as a violation.
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Use an explicit nonfaulting load to ignore the ADI tag.
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This patch should now work with both Studio and gcc compilers (and possibly
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many others). It might be pushed upstream.
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--- Python-3.9.0/Objects/obmalloc.c
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+++ Python-3.9.0/Objects/obmalloc.c
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@@ -1407,6 +1407,38 @@ obmalloc controls. Since this test is n
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extremely desirable that it be this fast.
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*/
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+#ifdef __sparcv9
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+/*
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+ * Py_ADDRESS_IN_RANGE needs to access memory that might be arbitrarily
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+ * tagged by an ADI aware allocator. The use of a nonfaulting load
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+ * guarantees that the read will succeed.
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+ */
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+#ifdef __SUNPRO_C
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+
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+/* Studio can use built-in nonfaulting load instruction for vis.h */
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+#include <vis.h>
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+#define POOL_INDEX(x) __vis_ldswa_ASI_PNF((void*)x)
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+
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+#else /* __SUNPRO_C */
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+/*
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+ * GCC doesn't have similar instruction built-in, but it can use
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+ * following assembly code to do the same.
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+ */
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+
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+static inline int vis_ldswa_ASI_PNF(void *arg);
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+
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+int vis_ldswa_ASI_PNF(void *arg) {
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+ int res;
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+ __asm__ ("ldswa [%1]0x82,%0" : "=r" (res) : "r" (arg));
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+ return res;
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+}
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+#define POOL_INDEX(x) vis_ldswa_ASI_PNF((void*)x)
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+
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+#endif /* __SUNPRO_C */
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+#else /* __sparcv9 */
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+#define POOL_INDEX(x) (*(x))
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+#endif /* __sparcv9 */
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+
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static bool _Py_NO_SANITIZE_ADDRESS
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_Py_NO_SANITIZE_THREAD
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_Py_NO_SANITIZE_MEMORY
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@@ -1417,7 +1449,7 @@ address_in_range(void *p, poolp pool)
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// another thread may be concurrently modifying the value without holding
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// the GIL. The following dance forces the compiler to read pool->arenaindex
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// only once.
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- uint arenaindex = *((volatile uint *)&pool->arenaindex);
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+ uint arenaindex = (uint)POOL_INDEX((volatile uint *)&pool->arenaindex);
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return arenaindex < maxarenas &&
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(uintptr_t)p - arenas[arenaindex].address < ARENA_SIZE &&
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arenas[arenaindex].address != 0;
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