Repository: spark Updated Branches: refs/heads/branch-1.6 ab2a124c8 -> 1cf9d3858
[SPARK-12030] Fix Platform.copyMemory to handle overlapping regions. This bug was exposed as memory corruption in Timsort which uses copyMemory to copy large regions that can overlap. The prior implementation did not handle this case half the time and always copied forward, resulting in the data being corrupt. Author: Nong Li <n...@databricks.com> Closes #10068 from nongli/spark-12030. (cherry picked from commit 2cef1cdfbb5393270ae83179b6a4e50c3cbf9e93) Signed-off-by: Yin Huai <yh...@databricks.com> Project: http://git-wip-us.apache.org/repos/asf/spark/repo Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/1cf9d385 Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/1cf9d385 Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/1cf9d385 Branch: refs/heads/branch-1.6 Commit: 1cf9d3858c8a3a5796b64a9fbea22509f02d778a Parents: ab2a124 Author: Nong Li <n...@databricks.com> Authored: Tue Dec 1 12:59:53 2015 -0800 Committer: Yin Huai <yh...@databricks.com> Committed: Tue Dec 1 13:00:05 2015 -0800 ---------------------------------------------------------------------- .../java/org/apache/spark/unsafe/Platform.java | 27 +++++++-- .../apache/spark/unsafe/PlatformUtilSuite.java | 61 ++++++++++++++++++++ 2 files changed, 82 insertions(+), 6 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/spark/blob/1cf9d385/unsafe/src/main/java/org/apache/spark/unsafe/Platform.java ---------------------------------------------------------------------- diff --git a/unsafe/src/main/java/org/apache/spark/unsafe/Platform.java b/unsafe/src/main/java/org/apache/spark/unsafe/Platform.java index 1c16da9..0d6b215 100644 --- a/unsafe/src/main/java/org/apache/spark/unsafe/Platform.java +++ b/unsafe/src/main/java/org/apache/spark/unsafe/Platform.java @@ -107,12 +107,27 @@ public final class Platform { public static void copyMemory( Object src, long srcOffset, Object dst, long dstOffset, long length) { - while (length > 0) { - long size = Math.min(length, UNSAFE_COPY_THRESHOLD); - _UNSAFE.copyMemory(src, srcOffset, dst, dstOffset, size); - length -= size; - srcOffset += size; - dstOffset += size; + // Check if dstOffset is before or after srcOffset to determine if we should copy + // forward or backwards. This is necessary in case src and dst overlap. + if (dstOffset < srcOffset) { + while (length > 0) { + long size = Math.min(length, UNSAFE_COPY_THRESHOLD); + _UNSAFE.copyMemory(src, srcOffset, dst, dstOffset, size); + length -= size; + srcOffset += size; + dstOffset += size; + } + } else { + srcOffset += length; + dstOffset += length; + while (length > 0) { + long size = Math.min(length, UNSAFE_COPY_THRESHOLD); + srcOffset -= size; + dstOffset -= size; + _UNSAFE.copyMemory(src, srcOffset, dst, dstOffset, size); + length -= size; + } + } } http://git-wip-us.apache.org/repos/asf/spark/blob/1cf9d385/unsafe/src/test/java/org/apache/spark/unsafe/PlatformUtilSuite.java ---------------------------------------------------------------------- diff --git a/unsafe/src/test/java/org/apache/spark/unsafe/PlatformUtilSuite.java b/unsafe/src/test/java/org/apache/spark/unsafe/PlatformUtilSuite.java new file mode 100644 index 0000000..693ec6e --- /dev/null +++ b/unsafe/src/test/java/org/apache/spark/unsafe/PlatformUtilSuite.java @@ -0,0 +1,61 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.spark.unsafe; + +import org.junit.Assert; +import org.junit.Test; + +public class PlatformUtilSuite { + + @Test + public void overlappingCopyMemory() { + byte[] data = new byte[3 * 1024 * 1024]; + int size = 2 * 1024 * 1024; + for (int i = 0; i < data.length; ++i) { + data[i] = (byte)i; + } + + Platform.copyMemory(data, Platform.BYTE_ARRAY_OFFSET, data, Platform.BYTE_ARRAY_OFFSET, size); + for (int i = 0; i < data.length; ++i) { + Assert.assertEquals((byte)i, data[i]); + } + + Platform.copyMemory( + data, + Platform.BYTE_ARRAY_OFFSET + 1, + data, + Platform.BYTE_ARRAY_OFFSET, + size); + for (int i = 0; i < size; ++i) { + Assert.assertEquals((byte)(i + 1), data[i]); + } + + for (int i = 0; i < data.length; ++i) { + data[i] = (byte)i; + } + Platform.copyMemory( + data, + Platform.BYTE_ARRAY_OFFSET, + data, + Platform.BYTE_ARRAY_OFFSET + 1, + size); + for (int i = 0; i < size; ++i) { + Assert.assertEquals((byte)i, data[i + 1]); + } + } +} --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@spark.apache.org For additional commands, e-mail: commits-h...@spark.apache.org
