Check isCanceled before calling eof on the input ReadBuffer in TCPHandler

alexey-milovidov · claude · alexey-milovidov · commit 1aa7ce7f878e · 2026-03-24T20:43:03.000+01:00
When waiting for a new query between requests, `TCPHandler::runImpl` calls `in->eof()` at line 495 to detect client disconnection. If the `ReadBuffer` was previously canceled (e.g., due to a failed read during a prior query's callback), calling `eof()` triggers `next()`, which hits `chassert(!isCanceled())` and aborts the server. Add an `in->isCanceled()` check before `in->eof()` in the condition, matching the pattern already used in `receivePacketsExpectCancel`. Also guard the `in->eof()` call in the `LOG_TEST` message to avoid evaluating it on a canceled buffer (function arguments are not short-circuit evaluated unlike `||`). https://s3.amazonaws.com/clickhouse-test-reports/json.html?PR=99537&sha=7338429ff8d3349ba147f9ba05558bbd6b84e4b2&name_0=PR&name_1=Stress%20test%20%28amd_tsan%29 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
diff --git a/src/Server/TCPHandler.cpp b/src/Server/TCPHandler.cpp
@@ -492,9 +492,11 @@ void TCPHandler::runImpl()
             }
 
             /// If we need to shut down, or client disconnects.
-            if (!tcp_server.isOpen() || server.isCancelled() || in->eof())
+            if (!tcp_server.isOpen() || server.isCancelled() || in->isCanceled() || in->eof())
             {
-                LOG_TEST(log, "Closing connection (open: {}, cancelled: {}, eof: {})", tcp_server.isOpen(), server.isCancelled(), in->eof());
+                LOG_TEST(log, "Closing connection (open: {}, cancelled: {}, in_canceled: {}, eof: {})",
+                    tcp_server.isOpen(), server.isCancelled(), in->isCanceled(),
+                    !in->isCanceled() && in->eof());
                 return;
             }
         }

Original file line number	Diff line number	Diff line change
`@@ -492,9 +492,11 @@ void TCPHandler::runImpl()`
`492`	`492`	`}`
`493`	`493`
`494`	`494`	`/// If we need to shut down, or client disconnects.`
`495`		`- if (!tcp_server.isOpen() \|\| server.isCancelled() \|\| in->eof())`
	`495`	`+ if (!tcp_server.isOpen() \|\| server.isCancelled() \|\| in->isCanceled() \|\| in->eof())`
`496`	`496`	`{`
`497`		`- LOG_TEST(log, "Closing connection (open: {}, cancelled: {}, eof: {})", tcp_server.isOpen(), server.isCancelled(), in->eof());`
	`497`	`+ LOG_TEST(log, "Closing connection (open: {}, cancelled: {}, in_canceled: {}, eof: {})",`
	`498`	`+ tcp_server.isOpen(), server.isCancelled(), in->isCanceled(),`
	`499`	`+ !in->isCanceled() && in->eof());`
`498`	`500`	`return;`
`499`	`501`	`}`
`500`	`502`	`}`