From 6e5febe96410650957404461f68942c638ed94b5 Mon Sep 17 00:00:00 2001
From: "Uwe L. Korn" <uwelk@xhochy.com>
Date: Tue, 27 Feb 2018 08:53:46 +0100
Subject: [PATCH] ARROW-2210: [C++] Reset ptr on failed memory allocation

---
 cpp/src/arrow/memory_pool.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/cpp/src/arrow/memory_pool.cc b/cpp/src/arrow/memory_pool.cc
index b8cd9c2fcf9..dedab7ea729 100644
--- a/cpp/src/arrow/memory_pool.cc
+++ b/cpp/src/arrow/memory_pool.cc
@@ -107,10 +107,12 @@ class DefaultMemoryPool : public MemoryPool {
 
   Status Reallocate(int64_t old_size, int64_t new_size, uint8_t** ptr) override {
 #ifdef ARROW_JEMALLOC
+    uint8_t* previous_ptr = *ptr;
     *ptr = reinterpret_cast<uint8_t*>(rallocx(*ptr, new_size, MALLOCX_ALIGN(kAlignment)));
     if (*ptr == NULL) {
       std::stringstream ss;
       ss << "realloc of size " << new_size << " failed";
+      *ptr = previous_ptr;
       return Status::OutOfMemory(ss.str());
     }
 #else