197 lines
7.5 KiB
Diff
197 lines
7.5 KiB
Diff
From 5da786ef2a708559f5b53a05b7db6de0b64ce885 Mon Sep 17 00:00:00 2001
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From: Alex Rousskov <rousskov@measurement-factory.com>
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Date: Mon, 11 Sep 2023 07:49:36 +0000
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Subject: [PATCH] Bug 4156: comm.cc "!commHasHalfClosedMonitor(fd)" assertion
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(#1443)
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This bug is specific to "half_closed_clients on" configurations.
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assertion failed: ... "isOpen(fd) && !commHasHalfClosedMonitor(fd)"
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location: comm.cc:1583 in commStartHalfClosedMonitor()
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Squid asserts because Server schedules comm_read() after receiving EOF:
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That extra read results in another EOF notification, and an attempt to
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start monitoring an already monitored half-closed connection.
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Upon detecting a potentially half-closed connection,
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Server::doClientRead() should clear flags.readMore to prevent Server
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from scheduling another comm_read(), but it does not and cannot do that
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(without significant refactoring) because
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* Server does not have access to flags.readMore
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* flags.readMore hack is used for more than just "read more"
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We worked around the above limitation by re-detecting half-closed
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conditions and clearing flags.readMore after clientParseRequests(). That
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fixed the bug but further increased poor code duplication across
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ConnStateData::afterClientRead() and ConnStateData::kick() methods. We
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then refactored by merging and moving that duplicated code into
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clientParseRequests() and renamed that method to make backports safer.
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Conflict: NA
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Reference: https://github.com/squid-cache/squid/commit/5da786
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---
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src/client_side.cc | 67 ++++++++++++-----------------------
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src/client_side.h | 2 +-
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src/tests/stub_client_side.cc | 2 +-
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3 files changed, 24 insertions(+), 47 deletions(-)
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diff --git a/src/client_side.cc b/src/client_side.cc
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index e62bcf0fc7d..bd9cf6a7d5f 100644
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--- a/src/client_side.cc
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+++ b/src/client_side.cc
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@@ -932,7 +932,7 @@ ConnStateData::kick()
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* We are done with the response, and we are either still receiving request
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* body (early response!) or have already stopped receiving anything.
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*
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- * If we are still receiving, then clientParseRequest() below will fail.
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+ * If we are still receiving, then parseRequests() below will fail.
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* (XXX: but then we will call readNextRequest() which may succeed and
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* execute a smuggled request as we are not done with the current request).
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*
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@@ -952,28 +952,12 @@ ConnStateData::kick()
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* Attempt to parse a request from the request buffer.
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* If we've been fed a pipelined request it may already
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* be in our read buffer.
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- *
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- \par
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- * This needs to fall through - if we're unlucky and parse the _last_ request
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- * from our read buffer we may never re-register for another client read.
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*/
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- if (clientParseRequests()) {
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- debugs(33, 3, clientConnection << ": parsed next request from buffer");
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- }
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+ parseRequests();
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- /** \par
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- * Either we need to kick-start another read or, if we have
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- * a half-closed connection, kill it after the last request.
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- * This saves waiting for half-closed connections to finished being
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- * half-closed _AND_ then, sometimes, spending "Timeout" time in
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- * the keepalive "Waiting for next request" state.
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- */
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- if (commIsHalfClosed(clientConnection->fd) && pipeline.empty()) {
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- debugs(33, 3, "half-closed client with no pending requests, closing");
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- clientConnection->close();
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+ if (!isOpen())
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return;
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- }
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/** \par
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* At this point we either have a parsed request (which we've
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@@ -1882,16 +1866,11 @@ ConnStateData::receivedFirstByte()
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resetReadTimeout(Config.Timeout.request);
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}
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-/**
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- * Attempt to parse one or more requests from the input buffer.
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- * Returns true after completing parsing of at least one request [header]. That
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- * includes cases where parsing ended with an error (e.g., a huge request).
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- */
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-bool
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-ConnStateData::clientParseRequests()
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+/// Attempt to parse one or more requests from the input buffer.
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+/// May close the connection.
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+void
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+ConnStateData::parseRequests()
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{
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- bool parsed_req = false;
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-
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debugs(33, 5, clientConnection << ": attempting to parse");
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// Loop while we have read bytes that are not needed for producing the body
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@@ -1936,8 +1915,6 @@ ConnStateData::clientParseRequests()
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processParsedRequest(context);
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- parsed_req = true; // XXX: do we really need to parse everything right NOW ?
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-
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if (context->mayUseConnection()) {
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debugs(33, 3, "Not parsing new requests, as this request may need the connection");
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break;
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@@ -1950,8 +1927,19 @@ ConnStateData::clientParseRequests()
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}
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}
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- /* XXX where to 'finish' the parsing pass? */
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- return parsed_req;
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+ debugs(33, 7, "buffered leftovers: " << inBuf.length());
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+
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+ if (isOpen() && commIsHalfClosed(clientConnection->fd)) {
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+ if (pipeline.empty()) {
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+ // we processed what we could parse, and no more data is coming
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+ debugs(33, 5, "closing half-closed without parsed requests: " << clientConnection);
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+ clientConnection->close();
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+ } else {
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+ // we parsed what we could, and no more data is coming
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+ debugs(33, 5, "monitoring half-closed while processing parsed requests: " << clientConnection);
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+ flags.readMore = false; // may already be false
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+ }
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+ }
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}
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void
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@@ -1968,18 +1956,7 @@ ConnStateData::afterClientRead()
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if (pipeline.empty())
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fd_note(clientConnection->fd, "Reading next request");
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- if (!clientParseRequests()) {
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- if (!isOpen())
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- return;
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- // We may get here if the client half-closed after sending a partial
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- // request. See doClientRead() and shouldCloseOnEof().
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- // XXX: This partially duplicates ConnStateData::kick().
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- if (pipeline.empty() && commIsHalfClosed(clientConnection->fd)) {
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- debugs(33, 5, clientConnection << ": half-closed connection, no completed request parsed, connection closing.");
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- clientConnection->close();
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- return;
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- }
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- }
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+ parseRequests();
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if (!isOpen())
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return;
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@@ -3767,7 +3744,7 @@ ConnStateData::notePinnedConnectionBecameIdle(PinnedIdleContext pic)
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startPinnedConnectionMonitoring();
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if (pipeline.empty())
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- kick(); // in case clientParseRequests() was blocked by a busy pic.connection
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+ kick(); // in case parseRequests() was blocked by a busy pic.connection
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}
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/// Forward future client requests using the given server connection.
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diff --git a/src/client_side.h b/src/client_side.h
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index e37ab27da1a..9f36d864c2c 100644
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--- a/src/client_side.h
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+++ b/src/client_side.h
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@@ -98,7 +98,6 @@ class ConnStateData:
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void doneWithControlMsg() override;
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/// Traffic parsing
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- bool clientParseRequests();
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void readNextRequest();
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/// try to make progress on a transaction or read more I/O
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@@ -443,6 +442,7 @@ class ConnStateData:
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void checkLogging();
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+ void parseRequests();
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void clientAfterReadingRequests();
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bool concurrentRequestQueueFilled() const;
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diff --git a/src/tests/stub_client_side.cc b/src/tests/stub_client_side.cc
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index 8c160e56340..f49d5dceeed 100644
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--- a/src/tests/stub_client_side.cc
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+++ b/src/tests/stub_client_side.cc
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@@ -14,7 +14,7 @@
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#include "tests/STUB.h"
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#include "client_side.h"
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-bool ConnStateData::clientParseRequests() STUB_RETVAL(false)
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+void ConnStateData::parseRequests() STUB
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void ConnStateData::readNextRequest() STUB
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bool ConnStateData::isOpen() const STUB_RETVAL(false)
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void ConnStateData::kick() STUB
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