fix invalid memory address or nil pointer dereference#10
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The net.Conn must be captured in the defer, so the shadowed variable didn't cause the panic, when the error happens in RemoveLabelHeaderFromStream. Signed-off-by: Vladimir Varankin <vladimir.varankin@grafana.com>
jesusvazquez
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Would it make sense to rename the conn below?
conn, streamLabel, err = RemoveLabelHeaderFromStream(conn)
pracucci
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Nov 24, 2025
net.go
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| // handleConn handles a single incoming stream connection from the transport. | ||
| func (m *Memberlist) handleConn(conn net.Conn) { | ||
| defer func() { | ||
| defer func(conn net.Conn) { |
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This is safe because the wrapped net.Conn returned by RemoveLabelHeaderFromStream() doesn't override the Close() but if in the future it will do it (unlikely honestly), then this change will trigger a latent bug. Maybe you can save a reference to the original connection instead, and close the wrapped if != nil and fallback to the original one?
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I see the concern. I think the added test would catch this scenario. But I've also addressed it in e2d1a17 — I think it's simpler, and easier to follow like that.
Signed-off-by: Vladimir Varankin <vladimir.varankin@grafana.com>
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Similar to #7 (comment) the CI seems very flaky 😥
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This was referenced Nov 24, 2025
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**What this PR does**: The PR updates our member fork to bring changes grafana/memberlist#10 > fix invalid memory address or nil pointer dereference **Which issue(s) this PR fixes**: Relates to grafana/mimir#13287 Signed-off-by: Vladimir Varankin <vladimir.varankin@grafana.com>
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#### What this PR does The PR updates our member fork to bring changes grafana/memberlist#10 #### Which issue(s) this PR fixes or relates to Closes #13287 #### Checklist - [ ] Tests updated. - [ ] Documentation added. - [x] `CHANGELOG.md` updated - the order of entries should be `[CHANGE]`, `[FEATURE]`, `[ENHANCEMENT]`, `[BUGFIX]`. If changelog entry is not needed, please add the `changelog-not-needed` label to the PR. - [ ] [`about-versioning.md`](https://github.com/grafana/mimir/blob/main/docs/sources/mimir/configure/about-versioning.md) updated with experimental features. --------- Signed-off-by: Vladimir Varankin <vladimir.varankin@grafana.com>
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This is the fixup for changes in hashicorp#325
The
net.Connmust be captured in thedeferinside thehandleConn, so the shadowed variable didn't cause panic, when the error happens inside theRemoveLabelHeaderFromStream.Note, I will open a PR to fix this upstream later.
Relates to grafana/mimir#13287