database/sql: ensure releaseConn is defined before a possible close
When running a Query on Stmt a dependency is added to the stmt and
rows. To do that it needs a reference to Rows, so the releaseConn
function is defined after the definition. However the
rows.initContextClose was set to run before the releaseConn was
set on rows, setting up a situation where the connection could
be canceled before the releaseConn was set and resulting in
a segfault.
Fixes #20160
Change-Id: I5592e7db2cf653dfc48d42cbc2b03ca20501b1a0
Reviewed-on: https://go-review.googlesource.com/42139
Run-TryBot: Daniel Theophanes <kardianos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/database/sql/sql_test.go b/src/database/sql/sql_test.go
index 5ea965f..2fd81f2 100644
--- a/src/database/sql/sql_test.go
+++ b/src/database/sql/sql_test.go
@@ -3044,6 +3044,46 @@
wg.Wait()
}
+// TestIssue20160 attempts to test a short context life on a stmt Query.
+func TestIssue20160(t *testing.T) {
+ db := newTestDB(t, "people")
+ defer closeDB(t, db)
+
+ ctx := context.Background()
+ sem := make(chan bool, 20)
+ var wg sync.WaitGroup
+
+ const milliWait = 30
+
+ stmt, err := db.PrepareContext(ctx, "SELECT|people|name|")
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer stmt.Close()
+
+ for i := 0; i < 100; i++ {
+ sem <- true
+ wg.Add(1)
+ go func() {
+ defer func() {
+ <-sem
+ wg.Done()
+ }()
+ ctx, cancel := context.WithTimeout(ctx, time.Duration(rand.Intn(milliWait))*time.Millisecond)
+ defer cancel()
+
+ // This is expected to give a cancel error most, but not all the time.
+ // Test failure will happen with a panic or other race condition being
+ // reported.
+ rows, _ := stmt.QueryContext(ctx)
+ if rows != nil {
+ rows.Close()
+ }
+ }()
+ }
+ wg.Wait()
+}
+
// TestIssue18719 closes the context right before use. The sql.driverConn
// will nil out the ci on close in a lock, but if another process uses it right after
// it will panic with on the nil ref.
