This is an automated email from the ASF dual-hosted git repository.
markt pushed a commit to branch 8.5.x
in repository https://gitbox.apache.org/repos/asf/tomcat.git
commit d57e1ca2fc25c9234caed8d74ec741585ff59256
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Fri Sep 13 16:37:55 2019 +0100
Fix https://bz.apache.org/bugzilla/show_bug.cgi?id=63682 HTTP/2 hang
Fix a potential hang when using the asynchronous Servlet API to write
the response body and the stream and/or connection window reaches 0
bytes in size.
---
java/org/apache/coyote/http2/Stream.java | 12 +++++++++---
.../apache/coyote/http2/WindowAllocationManager.java | 17 +++++++++++++++++
webapps/docs/changelog.xml | 5 +++++
3 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/java/org/apache/coyote/http2/Stream.java
b/java/org/apache/coyote/http2/Stream.java
index a25edfe..6b6eb93 100644
--- a/java/org/apache/coyote/http2/Stream.java
+++ b/java/org/apache/coyote/http2/Stream.java
@@ -937,12 +937,18 @@ public class Stream extends AbstractStream implements
HeaderEmitter {
}
synchronized boolean isReady() {
- if (getWindowSize() > 0 && handler.getWindowSize() > 0 &&
!dataLeft) {
- return true;
- } else {
+ // Bug 63682
+ // Only want to return false if the window size is zero AND we are
+ // already waiting for an allocation.
+ if (getWindowSize() > 0 && allocationManager.isWaitingForStream()
||
+ handler.getWindowSize() > 0 &&
allocationManager.isWaitingForConnection() ||
+ dataLeft) {
writeInterest = true;
return false;
+ } else {
+ return true;
}
+
}
synchronized boolean isRegisteredForWrite() {
diff --git a/java/org/apache/coyote/http2/WindowAllocationManager.java
b/java/org/apache/coyote/http2/WindowAllocationManager.java
index da7aebe..f286430 100644
--- a/java/org/apache/coyote/http2/WindowAllocationManager.java
+++ b/java/org/apache/coyote/http2/WindowAllocationManager.java
@@ -119,6 +119,23 @@ class WindowAllocationManager {
}
+ boolean isWaitingForStream() {
+ return isWaitingFor(STREAM);
+ }
+
+
+ boolean isWaitingForConnection() {
+ return isWaitingFor(CONNECTION);
+ }
+
+
+ private boolean isWaitingFor(int waitTarget) {
+ synchronized (stream) {
+ return (waitingFor & waitTarget) > 0;
+ }
+ }
+
+
private void waitFor(int waitTarget, long timeout) throws
InterruptedException {
synchronized (stream) {
if (waitingFor != NONE) {
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index a0e538e..75c640c 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -62,6 +62,11 @@
<subsection name="Coyote">
<changelog>
<fix>
+ <bug>63682</bug>: Fix a potential hang when using the asynchronous
+ Servlet API to write the response body and the stream and/or connection
+ window reaches 0 bytes in size. (markt)
+ </fix>
+ <fix>
<bug>63690</bug>: Use the average of the current and previous sizes
when
calculating overhead for HTTP/2 <code>DATA</code> and
<code>WINDOW_UPDATE</code> frames to avoid false positives as a result
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