[compiler-rt] [msan] Mark allocator padding as uninitialized, with new origin tag (PR #157187)

[Thurston Dang via llvm-commits]

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@@ -22,6 +22,7 @@ MSAN_FLAG(int, origin_history_size, Origin::kMaxDepth, "")
 MSAN_FLAG(int, origin_history_per_stack_limit, 20000, "")
 MSAN_FLAG(bool, poison_heap_with_zeroes, false, "")
 MSAN_FLAG(bool, poison_stack_with_zeroes, false, "")
+MSAN_FLAG(bool, poison_in_calloc, true, "")
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thurstond wrote:

posix_memalign shares the (misleadingly-named) `poison_in_malloc` flag.

It would deepen the confusion if calloc shared the `poison_in_malloc` flag.

https://github.com/llvm/llvm-project/pull/157187