Make readOnlyBearerAuth volatile to prevent data races when executing… #4375
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… concurrently doPullBearerAuth() and/or doPushBearerAuth()
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I have created a related issue here: #4374
Description of the issue and possible solution:
There is a data race (according to the Java memory model) in the field
readOnlyBearerAuthin classRegistryClient.java. Due to this data race, it is possible that writes on the variable by one thread are not visible to other threads reading the variable in the future. This can happen, for instance, if two threads concurrent executedoPullBearerAuth()anddoPushBearerAuth(). Here is an example of a thread reading stale or outdated values ofreadOnlyBearerAuth:Consider two threads t1 and t2 and let
readOnlyBearerAuth==false. Consider that t1 executesdoPullBearerAuth()and concurrently t2 executesdoPushBearerAuth(). The following execution can occur:readOnlyBearerAuthas false in this linereadOnlyBearerAuthas false (because there is no happens-before relation between the write by t1 and this read and the java memory model does not ensure that the write by t1 is visible to t2)Solution to the problem in this PR
Declaring
readOnlyBearerAuthas volatile. This removes the data race, and it ensures (as per the java memory model) that the reads always read the latest write onreadOnlyBearerAuthPriority
The execution above may not always occur, but, when it does, it will set incorrectly
authorizationin the classRegistryClient.java.Fixes #4374 🛠️