Fix pRequestInfo INVALID_POINTER_READ caused by GCs (v6 backport)

[NGloreous]

Fix pRequestInfo INVALID_POINTER_READ caused by GCs

• You've read the Contributor Guide and Code of Conduct.
• You've included unit or integration tests for your change, where applicable.
• You've included inline docs for your change, where applicable.
• There's an open issue for the PR that you are making. If you'd like to propose a new feature or change, please open an issue to discuss the change or find an existing issue.

Backports #50446 to v6.

Description

When using the IHttpSysRequestInfoFeature it's possible to hit invalid pointer read errors which causes a process crash. It's also possible to hit other issue caused by the invalid pointer. The error occurs when a GC moves to memory of the request's _backingBuffer before trying to access the RequestInfo property of IHttpSysRequestInfoFeature.

The fix is to adjust the pRequestInfo pointer similar to how other pointers in this class are adjusted.

Fixes #50445

Customer Impact

It's not possible to use the IHttpSysRequestInfoFeature without eventually crashing the process due to the INVALID_POINTER_READ.

Regression?

• Yes
• No

Risk

• High
• Medium
• Low

The change is very small an in-line with how pointers are used/updated within NativeRequestContext.

Verification

• Manual (required)
• Automated

I haven't been able to reproduce the crash locally, but I was able to confirm this is the root caused from a crash dump. I did verify this change did not regress this feature.

Packaging changes reviewed?

• Yes
• No
• N/A

---

When servicing release/2.1

• Make necessary changes in eng/PatchConfig.props

[ghost]

Thanks for your PR, @NGloreous. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[ghost]

Hi @NGloreous. If this is not a tell-mode PR, please make sure to follow the instructions laid out in the servicing process document.
Otherwise, please add tell-mode label.

[ghost]

Hi @NGloreous. Please make sure you've updated the PR description to use the Shiproom Template. Also, make sure this PR is not marked as a draft and is ready-to-merge.

To learn more about how to prepare a servicing PR click here.

[ghost]

Hi @NGloreous. This PR was just approved to be included in the upcoming servicing release. Somebody from the @dotnet/aspnet-build team will get it merged when the branches are open. Until then, please make sure all the CI checks pass and the PR is reviewed.