[BUG] Unpredictable behavior that leads to tasks being indefinitely stalled.

[mirsaeedi]

Library name and version

Azure.Core 1.40.0

Describe the bug

We encountered unpredictable behavior and threading issues since upgrading to Azure.Identity 1.12.0, which we believe stems from a bug in Azure.Core 1.40.0. The problem leads to tasks or threads being indefinitely stalled.

In our efforts to pinpoint the cause, we analyzed a memory dump of our service, revealing that tasks are stuck in a method at BearerTokenAuthenticationPolicy L425 in Azure.Core. Further examination indicated that a commit to Azure Core in May introduced this bug. The issue occurs under specific conditions when the authentication token has expired, and the background refresh token attempt has failed or been canceled, causing CurrentTokenTcs.Task in L425 to remain unfulfilled and the waiting thread to be permanently blocked.

Teams link

Expected behavior

The task should not get stuck.

Actual behavior

The problem leads to tasks or threads being indefinitely stalled.

Reproduction Steps

We were not able to reproduce the issue. Though, from the code, it's obvious that the issue happens when the authentication token has expired, and the background refresh token attempt has failed or been canceled.

Environment

No response

[github-actions]

Thank you for your feedback. Tagging and routing to the team member best able to assist.

[jsquire]

Fixed via #44882 and expected to be released later this week for Azure.Core's July update.

[github-actions]

Hi @mirsaeedi. Thank you for opening this issue and giving us the opportunity to assist. We believe that this has been addressed. If you feel that further discussion is needed, please add a comment with the text "/unresolve" to remove the "issue-addressed" label and continue the conversation.

[github-actions]

Hi @mirsaeedi, since you haven’t asked that we /unresolve the issue, we’ll close this out. If you believe further discussion is needed, please add a comment /unresolve to reopen the issue.

[KurzyukovAndrey]

@jsquire Do you plan to release Azure.Identity with Azure.Core >= 1.41 dependency?

[jsquire]

The next GA release of Identity will have an updated reference. There is no date that I can share at this time for that. The recommended mitigation in the meantime is to take a direct reference in your application on Azure.Core v1.41+ which will hoist the version used by Identity.

[KurzyukovAndrey]

Thank you for the update!