postgres.git / summary / log / commit / refs

commit    f8a4dd2e141a12e349882edecc683504acb82ec8
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Sat Jan 24 18:25:19 2015 +0000

    Fix unsafe coding in ReorderBufferCommit().
    
    "iterstate" must be marked volatile since it's changed inside the PG_TRY
    block and then used in the PG_CATCH stanza.  Noted by Mark Wilding of
    Salesforce.  (We really need to see if we can't get the C compiler to warn
    about this.)
    
    Also, reset iterstate to NULL after the mainline ReorderBufferIterTXNFinish
    call, to ensure the PG_CATCH block doesn't try to do that a second time.


 src/backend/replication/logical/reorderbuffer.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 6e668aeef1e..82f83d14505 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -1258,7 +1258,7 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
 					TimestampTz commit_time)
 {
 	ReorderBufferTXN *txn;
-	ReorderBufferIterTXNState *iterstate = NULL;
+	ReorderBufferIterTXNState *volatile iterstate = NULL;
 	ReorderBufferChange *change;
 
 	volatile CommandId command_id = FirstCommandId;
@@ -1303,7 +1303,6 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
 
 	PG_TRY();
 	{
-
 		/*
 		 * Decoding needs access to syscaches et al., which in turn use
 		 * heavyweight locks and such. Thus we need to have enough state
@@ -1472,7 +1471,9 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
 			}
 		}
 
+		/* clean up the iterator */
 		ReorderBufferIterTXNFinish(rb, iterstate);
+		iterstate = NULL;
 
 		/* call commit callback */
 		rb->commit(rb, txn, commit_lsn);
@@ -1639,7 +1640,7 @@ ReorderBufferForget(ReorderBuffer *rb, TransactionId xid, XLogRecPtr lsn)
 	 */
 	if (txn->base_snapshot != NULL && txn->ninvalidations > 0)
 	{
-		bool use_subtxn = IsTransactionOrTransactionBlock();
+		bool		use_subtxn = IsTransactionOrTransactionBlock();
 
 		if (use_subtxn)
 			BeginInternalSubTransaction("replay");


[parent: 586dd5d6a5d5]