3394654, 3393276 Revise FlushChannel() to account for the possibility

that the ChanWrite() call might recycle the buffer out from under us.

2 files changed, 7 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 8cbc045..db4bf84 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2011-08-19  Don Porter  <dgp@users.sourceforge.net>
 
+	* generic/tclIO.c: [Bugs 3394654, 3393276] Revise FlushChannel() to
+	account for the possibility that the ChanWrite() call might recycle
+	the buffer out from under us.
+
 	* generic/tclIO.c: Preserve the chanPtr during FlushChannel so that
 	channel drivers don't yank it away before we're done with it.
 
diff --git a/generic/tclIO.c b/generic/tclIO.c
index 946b53a..ae1b89a 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -2510,7 +2510,9 @@ FlushChannel(
 	    wroteSome = 1;
 	}
 
-	bufPtr->nextRemoved += written;
+	if (!IsBufferEmpty(bufPtr)) {
+	    bufPtr->nextRemoved += written;
+	}
 
 	/*
 	 * If this buffer is now empty, recycle it.