[Mlir-commits] [mlir] [mlir] DistinctAttributeAllocator: fix race (PR #132935)

[Mehdi Amini]

joker-eph wrote:

I suspect there is a more fundamental problem here.
If `PassManager::runWithCrashRecovery()`  is executed for multiple threads you can have the following sequence:

```
ctx->disableThreadLocalStorage(); // T1
ctx->disableThreadLocalStorage(); // T2
ctx->enableThreadLocalStorage(); // T1
```

At this point T2 can execute while the thread local storage it enabled again.
If we need to lock, I suspect the scope has to be for the entire duration of `PassManager::runWithCrashRecovery()` ; or use a semaphore  mechanism (increment an atomic integer instead of using a boolean).

Assuming I am correct with this, I would instead revert the original PR.

https://github.com/llvm/llvm-project/pull/132935