db: fix nil pointer dereference in SetContext

cockroachdb · Nov 7, 2023 · 81d9a4f · 81d9a4f
1 parent a0b01b6
commit 81d9a4f
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/level_iter.go b/level_iter.go
@@ -1234,9 +1234,11 @@ func (l *levelIter) SetBounds(lower, upper []byte) {
 
 func (l *levelIter) SetContext(ctx context.Context) {
 	l.ctx = ctx
-	// TODO(sumeer): this is losing the ctx = objiotracing.WithLevel(ctx,
-	// manifest.LevelToInt(opts.level)) that happens in table_cache.go.
-	l.iter.SetContext(ctx)
+	if l.iter != nil {
+		// TODO(sumeer): this is losing the ctx = objiotracing.WithLevel(ctx,
+		// manifest.LevelToInt(opts.level)) that happens in table_cache.go.
+		l.iter.SetContext(ctx)
+	}
 }
 
 func (l *levelIter) String() string {

diff --git a/merging_iter_test.go b/merging_iter_test.go
@@ -272,6 +272,10 @@ func TestMergingIterCornerCases(t *testing.T) {
 			miter.init(nil /* opts */, &stats, cmp, func(a []byte) int { return len(a) }, levelIters...)
 			defer miter.Close()
 			miter.forceEnableSeekOpt = true
+			// Exercise SetContext for fun
+			// (https://github.com/cockroachdb/pebble/pull/3037 caused a SIGSEGV due
+			// to a nil pointer dereference).
+			miter.SetContext(context.Background())
 			return runInternalIterCmd(t, d, miter, iterCmdVerboseKey, iterCmdStats(&stats))
 		default:
 			return fmt.Sprintf("unknown command: %s", d.Cmd)