Thank you filing this issue @euroelessar and welcome to Go!

So to help with a prognosis, proper fix for this issue and for posterity, it would be helpful to paste in here a runnable repro because the conditions that you are described are part of the usual x/net/http2.Transport usages.

In the meantime I'll page some http2 folks @rs @tombergan @bradfitz

Thanks, @odeke-em.
Pull request has a test which exposes the issue. Though let me try to combine some standalone example as well.

Standalone example: https://gist.github.com/euroelessar/6f4535db11b8bf024d85253cdaa1db1f
It fails against master x/net/http2 package (deadline on the last GET call due to exceeding concurrency limit).

In case of request body write error, the stream is not reset/forgotten. The following patch fixes the issue, though I'm not sure a cancel is the right response to such problem spec-wise:

diff --git a/http2/transport.go b/http2/transport.go
index 9d1f2fa..b5c8701 100644
--- a/http2/transport.go
+++ b/http2/transport.go
@@ -1060,7 +1060,12 @@ func (cc *ClientConn) roundTrip(req *http.Request) (res *http.Response, gotErrAf
                        default:
                        }
                        if err != nil {
-                          return nil, cs.getStartedWrite(), err
+                               startedWrite := cs.getStartedWrite()
+                               if startedWrite {
+                                       cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+                               }
+                               cc.forgetStreamID(cs.ID)
+                               return nil, startedWrite, err
                        }
                        bodyWritten = true
                        if d := cc.responseHeaderTimeout(); d != 0 {

Change https://golang.org/cl/132715 mentions this issue: http2: don't leak streams on broken body

This issue seems to be the same one behind googleapis/google-cloud-go#1211 and hashicorp/vault#5419.

I see this is attached to the Go 1.12 milestone, but the CL hasn't received any feedback. Are there plans to look at this?

I plan to look at it. Still targeted towards Go 1.12. (but could also be backported to Go 1.11.x)

Approved & submitted into x/net. Needs bundle into std.

Thanks for the fast response!

Thank you!
It would be great if the fix could be backported to 1.11

@gopherbot, please backport to Go 1.11.

Backport issue(s) opened: #28673 (for 1.11).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://golang.org/wiki/MinorReleases.

Change https://golang.org/cl/152080 mentions this issue: net/http: update bundled x/net/http2