From: Daniel Theophanes Date: Tue, 17 Oct 2017 22:59:56 +0000 (-0700) Subject: database/sql: ensure all driver interfaces are called under single lock X-Git-Tag: go1.10beta1~595 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=1126d1483f0397648905fcd4590ae45352cabd69;p=gostls13.git database/sql: ensure all driver interfaces are called under single lock Russ pointed out in a previous CL golang.org/cl/65731 that not only was the locking incomplete, previous changes did not correctly lock driver calls in other sections. After inspecting driverConn, driverStmt, driverResult, Tx, and Rows structs where driver interfaces are stored, I discovered a few more places that failed to lock driver calls. The largest of these was the parameter type converter "driverArgs". driverArgs was typically called right before another call to the driver in a locked region, so I made the entire driverArgs expect a locked driver mutex and combined the region. This should not be a problem because the connection is pulled out of the connection pool either way so there shouldn't be contention. Fixes #21117 Change-Id: I88d46f74dca25fb11a30f0bf8e79785a73133d23 Reviewed-on: https://go-review.googlesource.com/71433 Run-TryBot: Daniel Theophanes TryBot-Result: Gobot Gobot Reviewed-by: Russ Cox --- diff --git a/src/database/sql/convert.go b/src/database/sql/convert.go index c349a96edf..b44bed559d 100644 --- a/src/database/sql/convert.go +++ b/src/database/sql/convert.go @@ -12,7 +12,6 @@ import ( "fmt" "reflect" "strconv" - "sync" "time" "unicode" "unicode/utf8" @@ -38,17 +37,10 @@ func validateNamedValueName(name string) error { return fmt.Errorf("name %q does not begin with a letter", name) } -func driverNumInput(ds *driverStmt) int { - ds.Lock() - defer ds.Unlock() // in case NumInput panics - return ds.si.NumInput() -} - // ccChecker wraps the driver.ColumnConverter and allows it to be used // as if it were a NamedValueChecker. If the driver ColumnConverter // is not present then the NamedValueChecker will return driver.ErrSkip. type ccChecker struct { - sync.Locker cci driver.ColumnConverter want int } @@ -88,9 +80,7 @@ func (c ccChecker) CheckNamedValue(nv *driver.NamedValue) error { // same error. var err error arg := nv.Value - c.Lock() nv.Value, err = c.cci.ColumnConverter(index).ConvertValue(arg) - c.Unlock() if err != nil { return err } @@ -112,7 +102,7 @@ func defaultCheckNamedValue(nv *driver.NamedValue) (err error) { // Stmt.Query into driver Values. // // The statement ds may be nil, if no statement is available. -func driverArgs(ci driver.Conn, ds *driverStmt, args []interface{}) ([]driver.NamedValue, error) { +func driverArgsConnLocked(ci driver.Conn, ds *driverStmt, args []interface{}) ([]driver.NamedValue, error) { nvargs := make([]driver.NamedValue, len(args)) // -1 means the driver doesn't know how to count the number of @@ -124,8 +114,7 @@ func driverArgs(ci driver.Conn, ds *driverStmt, args []interface{}) ([]driver.Na var cc ccChecker if ds != nil { si = ds.si - want = driverNumInput(ds) - cc.Locker = ds.Locker + want = ds.si.NumInput() cc.want = want } diff --git a/src/database/sql/convert_test.go b/src/database/sql/convert_test.go index 35dbab3339..c198177760 100644 --- a/src/database/sql/convert_test.go +++ b/src/database/sql/convert_test.go @@ -481,7 +481,7 @@ func TestDriverArgs(t *testing.T) { } for i, tt := range tests { ds := &driverStmt{Locker: &sync.Mutex{}, si: stubDriverStmt{nil}} - got, err := driverArgs(nil, ds, tt.args) + got, err := driverArgsConnLocked(nil, ds, tt.args) if err != nil { t.Errorf("test[%d]: %v", i, err) continue diff --git a/src/database/sql/fakedb_test.go b/src/database/sql/fakedb_test.go index 070b783453..31e22a7a74 100644 --- a/src/database/sql/fakedb_test.go +++ b/src/database/sql/fakedb_test.go @@ -1005,6 +1005,7 @@ type rowsCursor struct { } func (rc *rowsCursor) touchMem() { + rc.parentMem.touchMem() rc.line++ } diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go index c17b2b543b..be73b5e372 100644 --- a/src/database/sql/sql.go +++ b/src/database/sql/sql.go @@ -1368,12 +1368,12 @@ func (db *DB) execDC(ctx context.Context, dc *driverConn, release func(error), q } if ok { var nvdargs []driver.NamedValue - nvdargs, err = driverArgs(dc.ci, nil, args) - if err != nil { - return nil, err - } var resi driver.Result withLock(dc, func() { + nvdargs, err = driverArgsConnLocked(dc.ci, nil, args) + if err != nil { + return + } resi, err = ctxDriverExec(ctx, execerCtx, execer, query, nvdargs) }) if err != driver.ErrSkip { @@ -1439,13 +1439,14 @@ func (db *DB) queryDC(ctx, txctx context.Context, dc *driverConn, releaseConn fu queryer, ok = dc.ci.(driver.Queryer) } if ok { - nvdargs, err := driverArgs(dc.ci, nil, args) - if err != nil { - releaseConn(err) - return nil, err - } + var nvdargs []driver.NamedValue var rowsi driver.Rows + var err error withLock(dc, func() { + nvdargs, err = driverArgsConnLocked(dc.ci, nil, args) + if err != nil { + return + } rowsi, err = ctxDriverQuery(ctx, queryerCtx, queryer, query, nvdargs) }) if err != driver.ErrSkip { @@ -2034,11 +2035,14 @@ func (tx *Tx) StmtContext(ctx context.Context, stmt *Stmt) *Stmt { stmt.mu.Unlock() if si == nil { - cs, err := stmt.prepareOnConnLocked(ctx, dc) + withLock(dc, func() { + var ds *driverStmt + ds, err = stmt.prepareOnConnLocked(ctx, dc) + si = ds.si + }) if err != nil { return &Stmt{stickyErr: err} } - si = cs.si } parentStmt = stmt } @@ -2230,14 +2234,14 @@ func (s *Stmt) Exec(args ...interface{}) (Result, error) { } func resultFromStatement(ctx context.Context, ci driver.Conn, ds *driverStmt, args ...interface{}) (Result, error) { - dargs, err := driverArgs(ci, ds, args) + ds.Lock() + defer ds.Unlock() + + dargs, err := driverArgsConnLocked(ci, ds, args) if err != nil { return nil, err } - ds.Lock() - defer ds.Unlock() - resi, err := ctxDriverStmtExec(ctx, ds.si, dargs) if err != nil { return nil, err @@ -2401,10 +2405,10 @@ func (s *Stmt) Query(args ...interface{}) (*Rows, error) { } func rowsiFromStatement(ctx context.Context, ci driver.Conn, ds *driverStmt, args ...interface{}) (driver.Rows, error) { - var want int - withLock(ds, func() { - want = ds.si.NumInput() - }) + ds.Lock() + defer ds.Unlock() + + want := ds.si.NumInput() // -1 means the driver doesn't know how to count the number of // placeholders, so we won't sanity check input here and instead let the @@ -2413,14 +2417,11 @@ func rowsiFromStatement(ctx context.Context, ci driver.Conn, ds *driverStmt, arg return nil, fmt.Errorf("sql: statement expects %d inputs; got %d", want, len(args)) } - dargs, err := driverArgs(ci, ds, args) + dargs, err := driverArgsConnLocked(ci, ds, args) if err != nil { return nil, err } - ds.Lock() - defer ds.Unlock() - rowsi, err := ctxDriverStmtQuery(ctx, ds.si, dargs) if err != nil { return nil, err @@ -2583,9 +2584,16 @@ func (rs *Rows) nextLocked() (doClose, ok bool) { if rs.closed { return false, false } + + // Lock the driver connection before calling the driver interface + // rowsi to prevent a Tx from rolling back the connection at the same time. + rs.dc.Lock() + defer rs.dc.Unlock() + if rs.lastcols == nil { rs.lastcols = make([]driver.Value, len(rs.rowsi.Columns())) } + rs.lasterr = rs.rowsi.Next(rs.lastcols) if rs.lasterr != nil { // Close the connection if there is a driver error. @@ -2635,6 +2643,12 @@ func (rs *Rows) NextResultSet() bool { doClose = true return false } + + // Lock the driver connection before calling the driver interface + // rowsi to prevent a Tx from rolling back the connection at the same time. + rs.dc.Lock() + defer rs.dc.Unlock() + rs.lasterr = nextResultSet.NextResultSet() if rs.lasterr != nil { doClose = true @@ -2666,6 +2680,9 @@ func (rs *Rows) Columns() ([]string, error) { if rs.rowsi == nil { return nil, errors.New("sql: no Rows available") } + rs.dc.Lock() + defer rs.dc.Unlock() + return rs.rowsi.Columns(), nil } @@ -2680,7 +2697,10 @@ func (rs *Rows) ColumnTypes() ([]*ColumnType, error) { if rs.rowsi == nil { return nil, errors.New("sql: no Rows available") } - return rowsColumnInfoSetup(rs.rowsi), nil + rs.dc.Lock() + defer rs.dc.Unlock() + + return rowsColumnInfoSetupConnLocked(rs.rowsi), nil } // ColumnType contains the name and type of a column. @@ -2741,7 +2761,7 @@ func (ci *ColumnType) DatabaseTypeName() string { return ci.databaseType } -func rowsColumnInfoSetup(rowsi driver.Rows) []*ColumnType { +func rowsColumnInfoSetupConnLocked(rowsi driver.Rows) []*ColumnType { names := rowsi.Columns() list := make([]*ColumnType, len(names)) diff --git a/src/database/sql/sql_test.go b/src/database/sql/sql_test.go index dead273503..f7b7d988e1 100644 --- a/src/database/sql/sql_test.go +++ b/src/database/sql/sql_test.go @@ -3157,6 +3157,9 @@ func TestIssue6081(t *testing.T) { // In the test, a context is canceled while the query is in process so // the internal rollback will run concurrently with the explicitly called // Tx.Rollback. +// +// The addition of calling rows.Next also tests +// Issue 21117. func TestIssue18429(t *testing.T) { db := newTestDB(t, "people") defer closeDB(t, db) @@ -3189,6 +3192,9 @@ func TestIssue18429(t *testing.T) { // reported. rows, _ := tx.QueryContext(ctx, "WAIT|"+qwait+"|SELECT|people|name|") if rows != nil { + // Call Next to test Issue 21117 and check for races. + for rows.Next() { + } rows.Close() } // This call will race with the context cancel rollback to complete