http2: avoid corruption in priority write scheduler

When removing a stream containing children in the priority tree, it was possible for some children to not be correctly moved to the parent of the removed stream. Fixes golang/go#66514 Change-Id: Ie8a8743a6213a6b1a2426e023111878afff78f9e Reviewed-on: https://go-review.googlesource.com/c/net/+/589255 LUCI-TryBot-Result: Go LUCI <[email protected]> Reviewed-by: Jonathan Amsterdam <[email protected]>
golang · May 30, 2024 · 5608279 · 5608279
1 parent 0d515a5
commit 5608279
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Showing 2 changed files with 36 additions and 2 deletions.
diff --git a/http2/writesched_priority.go b/http2/writesched_priority.go
@@ -443,8 +443,8 @@ func (ws *priorityWriteScheduler) addClosedOrIdleNode(list *[]*priorityNode, max
 }
 
 func (ws *priorityWriteScheduler) removeNode(n *priorityNode) {
- for k := n.kids; k != nil; k = k.next {
- k.setParent(n.parent)
+ for n.kids != nil {
+ n.kids.setParent(n.parent)
  }
  n.setParent(nil)
  delete(ws.nodes, n.id)

diff --git a/http2/writesched_priority_test.go b/http2/writesched_priority_test.go
@@ -562,3 +562,37 @@ func TestPriorityRstStreamOnNonOpenStreams(t *testing.T) {
  t.Error(err)
  }
 }
+
+// https://go.dev/issue/66514
+func TestPriorityIssue66514(t *testing.T) {
+ addDep := func(ws *priorityWriteScheduler, child uint32, parent uint32) {
+ ws.AdjustStream(child, PriorityParam{
+ StreamDep: parent,
+ Exclusive: false,
+ Weight: 16,
+ })
+ }
+
+ validateDepTree := func(ws *priorityWriteScheduler, id uint32, t *testing.T) {
+ for n := ws.nodes[id]; n != nil; n = n.parent {
+ if n.parent == nil {
+ if n.id != uint32(0) {
+ t.Errorf("detected nodes not parented to 0")
+ }
+ }
+ }
+ }
+
+ ws := NewPriorityWriteScheduler(nil).(*priorityWriteScheduler)
+
+ // Root entry
+ addDep(ws, uint32(1), uint32(0))
+ addDep(ws, uint32(3), uint32(1))
+ addDep(ws, uint32(5), uint32(1))
+
+ for id := uint32(7); id < uint32(100); id += uint32(4) {
+ addDep(ws, id, id-uint32(4))
+ addDep(ws, id+uint32(2), id-uint32(4))
+ validateDepTree(ws, id, t)
+ }
+}