[
https://issues.apache.org/jira/browse/SSHD-1341?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jiachen Lu updated SSHD-1341:
-----------------------------
Description:
h2. In a nutshell
I used some static analysis tools to discover a potential deadlock in version
2.4.0 of mina-sshd. I would like to know if it is a false positive.
The related lock objects and trace are shown below.
I look forward to the community's assistance in confirming this issue. Thank
you for your response. If you need more information, please feel free to
contact me.
This deadlock might be similar to SSHD-966
h2. Deadlock Pair
Deadlock `synchronized void flush() throws IOException` (Trace 1) and
`synchronized (encodeLock)` (Trace 2) acquire locks `this` in class
`ChannelOutputStream` and `encodeLock` in reverse orders.
./sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java
{code:java}
912 protected IoWriteFuture doWritePacket(Buffer buffer) throws IOException
{
913 // Synchronize all write requests as needed by the encoding
algorithm
914 // and also queue the write request in this synchronized block to
ensure
915 // packets are sent in the correct order
916 > synchronized (encodeLock) {
917 Buffer packet = resolveOutputPacket(buffer);
918 IoSession networkSession = getIoSession();
919 return networkSession.writePacket(packet);
920 }
921 }{code}
Deadlock `synchronized void flush() throws IOException` (Trace 1) and
`synchronized (encodeLock)` (Trace 2) acquire locks `this` in class
`ChannelOutputStream` and `encodeLock` in reverse orders.
./sshd-core/src/main/java/org/apache/sshd/server/forward/TcpipServerChannel.java
{code:java}
203 public void messageReceived(IoSession session, Readable message)
throws Exception {
204 if (isClosing()) {
205 if (debugEnabled) {
206 log.debug("doInit({}) Ignoring write to channel in
CLOSING state", TcpipServerChannel.this);
207 }
208 } else {
209 Buffer buffer = new ByteArrayBuffer(message.available()
+ Long.SIZE, false);
210 buffer.putBuffer(message);
211 out.write(buffer.array(), buffer.rpos(),
buffer.available());
212 > out.flush();
213 }
214 } {code}
h2. Trace
h3. Trace1
!image-2024-06-16-21-16-19-706.png!
h3.
h3. Trace2 !image-2024-06-16-21-16-41-229.png!
was:
h2. In a nutshell
I used some static analysis tools to discover a potential deadlock in version
2.4.0 of mina-sshd. I would like to know if it is a false positive.
The related lock objects and trace are shown below.
I look forward to the community's assistance in confirming this issue. Thank
you for your response. If you need more information, please feel free to
contact me.
This deadlock might be similar to SSHD-966
h2. Deadlock Pair
Deadlock `synchronized void flush() throws IOException` (Trace 1) and
`synchronized (encodeLock)` (Trace 2) acquire locks `this` in class
`ChannelOutputStream` and `encodeLock` in reverse orders.
./sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java
{code:java}
912 protected IoWriteFuture doWritePacket(Buffer buffer) throws IOException
{
913 // Synchronize all write requests as needed by the encoding
algorithm
914 // and also queue the write request in this synchronized block to
ensure
915 // packets are sent in the correct order
916 synchronized (encodeLock) {
917 Buffer packet = resolveOutputPacket(buffer);
918 IoSession networkSession = getIoSession();
919 return networkSession.writePacket(packet);
920 }
921 }{code}
Deadlock `synchronized void flush() throws IOException` (Trace 1) and
`synchronized (encodeLock)` (Trace 2) acquire locks `this` in class
`ChannelOutputStream` and `encodeLock` in reverse orders.
./sshd-core/src/main/java/org/apache/sshd/server/forward/TcpipServerChannel.java
{code:java}
203 public void messageReceived(IoSession session, Readable message)
throws Exception {
204 if (isClosing()) {
205 if (debugEnabled) {
206 log.debug("doInit({}) Ignoring write to channel in
CLOSING state", TcpipServerChannel.this);
207 }
208 } else {
209 Buffer buffer = new ByteArrayBuffer(message.available()
+ Long.SIZE, false);
210 buffer.putBuffer(message);
211 out.write(buffer.array(), buffer.rpos(),
buffer.available());
212 > out.flush();
213 }
214 } {code}
h2. Trace
h3. Trace1
!image-2024-06-16-21-16-19-706.png!
h3.
h3. Trace2 !image-2024-06-16-21-16-41-229.png!
> Deadlock in old version of SSHD
> -------------------------------
>
> Key: SSHD-1341
> URL: https://issues.apache.org/jira/browse/SSHD-1341
> Project: MINA SSHD
> Issue Type: Question
> Affects Versions: 2.4.0
> Reporter: Jiachen Lu
> Priority: Minor
> Attachments: image-2024-06-16-21-16-19-706.png,
> image-2024-06-16-21-16-41-229.png
>
>
> h2. In a nutshell
> I used some static analysis tools to discover a potential deadlock in version
> 2.4.0 of mina-sshd. I would like to know if it is a false positive.
>
> The related lock objects and trace are shown below.
>
> I look forward to the community's assistance in confirming this issue. Thank
> you for your response. If you need more information, please feel free to
> contact me.
>
> This deadlock might be similar to SSHD-966
>
> h2. Deadlock Pair
> Deadlock `synchronized void flush() throws IOException` (Trace 1) and
> `synchronized (encodeLock)` (Trace 2) acquire locks `this` in class
> `ChannelOutputStream` and `encodeLock` in reverse orders.
>
> ./sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java
>
> {code:java}
> 912 protected IoWriteFuture doWritePacket(Buffer buffer) throws
> IOException {
> 913 // Synchronize all write requests as needed by the encoding
> algorithm
> 914 // and also queue the write request in this synchronized block to
> ensure
> 915 // packets are sent in the correct order
> 916 > synchronized (encodeLock) {
> 917 Buffer packet = resolveOutputPacket(buffer);
> 918 IoSession networkSession = getIoSession();
> 919 return networkSession.writePacket(packet);
> 920 }
> 921 }{code}
>
>
>
> Deadlock `synchronized void flush() throws IOException` (Trace 1) and
> `synchronized (encodeLock)` (Trace 2) acquire locks `this` in class
> `ChannelOutputStream` and `encodeLock` in reverse orders.
>
> ./sshd-core/src/main/java/org/apache/sshd/server/forward/TcpipServerChannel.java
> {code:java}
> 203 public void messageReceived(IoSession session, Readable
> message) throws Exception {
> 204 if (isClosing()) {
> 205 if (debugEnabled) {
> 206 log.debug("doInit({}) Ignoring write to channel in
> CLOSING state", TcpipServerChannel.this);
> 207 }
> 208 } else {
> 209 Buffer buffer = new
> ByteArrayBuffer(message.available() + Long.SIZE, false);
> 210 buffer.putBuffer(message);
> 211 out.write(buffer.array(), buffer.rpos(),
> buffer.available());
> 212 > out.flush();
> 213 }
> 214 } {code}
> h2. Trace
> h3. Trace1
> !image-2024-06-16-21-16-19-706.png!
> h3.
> h3. Trace2 !image-2024-06-16-21-16-41-229.png!
>
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