What happens when an internal transaction reverts but the parent execution does not?

[siladu]

https://preethikasireddy.medium.com/how-does-ethereum-work-anyway-22d1df506369

One important thing to note is that internal transactions or messages don’t contain a gasLimit. This is because the gas limit is determined by the external creator of the original transaction (i.e. some externally owned account). The gas limit that the externally owned account sets must be high enough to carry out the transaction, including any sub-executions that occur as a result of that transaction, such as contract-to-contract messages. If, in the chain of transactions and messages, a particular message execution runs out of gas, then that message’s execution will revert, along with any subsequent messages triggered by the execution. However, the parent execution does not need to revert.

If the parent doesn't revert but an internal tx ran out of gas, doesn't that mean the parent gets reverted as well?

[siladu]

A child execution is not passed all of the parent's gas, 1/64 is held back. This helps prevent a fork bomb from too many nested calls. But that also means the parent execution should have some gas remaining.

https://ethereum.github.io/execution-specs/autoapi/ethereum/berlin/vm/gas/index.html#calculate-message-call-gas-stipend