From d7c532d8894ce806c9af13b8dd3eec975642b348 Mon Sep 17 00:00:00 2001 From: comex Date: Sat, 1 Jul 2023 15:00:39 -0700 Subject: Fixes and workarounds to make UBSan happier on macOS There are still some other issues not addressed here, but it's a start. Workarounds for false-positive reports: - `RasterizerAccelerated`: Put a gigantic array behind a `unique_ptr`, because UBSan has a [hardcoded limit](https://stackoverflow.com/questions/64531383/c-runtime-error-using-fsanitize-undefined-object-has-a-possibly-invalid-vp) of how big it thinks objects can be, specifically when dealing with offset-to-top values used with multiple inheritance. Hopefully this doesn't have a performance impact. - `QueryCacheBase::QueryCacheBase`: Avoid an operation that UBSan thinks is UB even though it at least arguably isn't. See the link in the comment for more information. Fixes for correct reports: - `PageTable`, `Memory`: Use `uintptr_t` values instead of pointers to avoid UB from pointer overflow (when pointer arithmetic wraps around the address space). - `KScheduler::Reload`: `thread->GetOwnerProcess()` can be `nullptr`; avoid calling methods on it in this case. (The existing code returns a garbage reference to a field, which is then passed into `LoadWatchpointArray`, and apparently it's never used, so it's harmless in practice but still triggers UBSan.) - `KAutoObject::Close`: This function calls `this->Destroy()`, which overwrites the beginning of the object with junk (specifically a free list pointer). Then it calls `this->UnregisterWithKernel()`. UBSan complains about a type mismatch because the vtable has been overwritten, and I believe this is indeed UB. `UnregisterWithKernel` also loads `m_kernel` from the 'freed' object, which seems to be technically safe (the overwriting doesn't extend as far as that field), but seems dubious. Switch to a `static` method and load `m_kernel` in advance. --- src/core/hle/kernel/k_thread.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/core/hle/kernel/k_thread.cpp') diff --git a/src/core/hle/kernel/k_thread.cpp b/src/core/hle/kernel/k_thread.cpp index adb6ec581..2a105a762 100644 --- a/src/core/hle/kernel/k_thread.cpp +++ b/src/core/hle/kernel/k_thread.cpp @@ -129,7 +129,7 @@ Result KThread::Initialize(KThreadFunction func, uintptr_t arg, KProcessAddress case ThreadType::User: ASSERT(((owner == nullptr) || (owner->GetCoreMask() | (1ULL << virt_core)) == owner->GetCoreMask())); - ASSERT(((owner == nullptr) || + ASSERT(((owner == nullptr) || (prio > Svc::LowestThreadPriority) || (owner->GetPriorityMask() | (1ULL << prio)) == owner->GetPriorityMask())); break; case ThreadType::Kernel: -- cgit v1.2.3