Fix BufferOverflowException during non-Unsafe PooledDirectByteBuf resize (#9912)

Motivation

Recent optimization #9765 introduced a bug where the native indices of
the internal reused duplicate nio buffer are not properly reset prior to
using it to copy data during a reallocation operation. This can result
in BufferOverflowExceptions thrown during ByteBuf capacity changes.

The code path in question applies only to pooled direct buffers when
Unsafe is disabled or not available.

Modification

Ensure ByteBuffer#clear() is always called on the reused internal nio
buffer prior to returning it from PooledByteBuf#internalNioBuffer()
(protected method); add unit test that exposes the bug.

Result

Fixes #9911
This commit is contained in:
Nick Hill 2020-01-10 21:04:32 -08:00 committed by Norman Maurer
parent ba140ac6bc
commit 607bc05a2c
3 changed files with 30 additions and 3 deletions

View File

@ -154,6 +154,8 @@ abstract class PooledByteBuf<T> extends AbstractReferenceCountedByteBuf {
ByteBuffer tmpNioBuf = this.tmpNioBuf;
if (tmpNioBuf == null) {
this.tmpNioBuf = tmpNioBuf = newInternalNioBuffer(memory);
} else {
tmpNioBuf.clear();
}
return tmpNioBuf;
}

View File

@ -260,7 +260,7 @@ final class PooledDirectByteBuf extends PooledByteBuf<ByteBuffer> {
}
index = idx(index);
tmpBuf.clear().position(index).limit(index + length);
tmpBuf.limit(index + length).position(index);
tmpBuf.put(src);
return this;
}
@ -274,7 +274,7 @@ final class PooledDirectByteBuf extends PooledByteBuf<ByteBuffer> {
return readBytes;
}
ByteBuffer tmpBuf = internalNioBuffer();
tmpBuf.clear().position(idx(index));
tmpBuf.position(idx(index));
tmpBuf.put(tmp, 0, readBytes);
return readBytes;
}

View File

@ -20,6 +20,8 @@ import io.netty.util.internal.PlatformDependent;
import org.junit.Assert;
import org.junit.Test;
import static org.junit.Assume.assumeTrue;
import java.nio.ByteBuffer;
public class PoolArenaTest {
@ -46,6 +48,7 @@ public class PoolArenaTest {
@Test
public void testDirectArenaOffsetCacheLine() throws Exception {
assumeTrue(PlatformDependent.hasUnsafe());
int capacity = 5;
int alignment = 128;
@ -64,7 +67,7 @@ public class PoolArenaTest {
}
@Test
public final void testAllocationCounter() {
public void testAllocationCounter() {
final PooledByteBufAllocator allocator = new PooledByteBufAllocator(
true, // preferDirect
0, // nHeapArena
@ -107,4 +110,26 @@ public class PoolArenaTest {
Assert.assertEquals(1, metric.numNormalDeallocations());
Assert.assertEquals(1, metric.numNormalAllocations());
}
@Test
public void testDirectArenaMemoryCopy() {
ByteBuf src = PooledByteBufAllocator.DEFAULT.directBuffer(512);
ByteBuf dst = PooledByteBufAllocator.DEFAULT.directBuffer(512);
PooledByteBuf<ByteBuffer> pooledSrc = unwrapIfNeeded(src);
PooledByteBuf<ByteBuffer> pooledDst = unwrapIfNeeded(dst);
// This causes the internal reused ByteBuffer duplicate limit to be set to 128
pooledDst.writeBytes(ByteBuffer.allocate(128));
// Ensure internal ByteBuffer duplicate limit is properly reset (used in memoryCopy non-Unsafe case)
pooledDst.chunk.arena.memoryCopy(pooledSrc.memory, 0, pooledDst, 512);
src.release();
dst.release();
}
@SuppressWarnings("unchecked")
private PooledByteBuf<ByteBuffer> unwrapIfNeeded(ByteBuf buf) {
return (PooledByteBuf<ByteBuffer>) (buf instanceof PooledByteBuf ? buf : buf.unwrap());
}
}