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| author | comex <comexk@gmail.com> | 2023-07-01 15:00:39 -0700 |
|---|---|---|
| committer | comex <comexk@gmail.com> | 2023-07-15 12:00:28 -0700 |
| commit | d7c532d8894ce806c9af13b8dd3eec975642b348 (patch) | |
| tree | 1353e6d1776384575019db28987e23237552a9de /src/video_core/query_cache.h | |
| parent | 04868ab9da2049429808a265dc50696f6300b2b4 (diff) | |
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.
Diffstat (limited to 'src/video_core/query_cache.h')
| -rw-r--r-- | src/video_core/query_cache.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/video_core/query_cache.h b/src/video_core/query_cache.h index 1528cc1dd..7047e2e63 100644 --- a/src/video_core/query_cache.h +++ b/src/video_core/query_cache.h @@ -103,7 +103,9 @@ public: explicit QueryCacheBase(VideoCore::RasterizerInterface& rasterizer_, Core::Memory::Memory& cpu_memory_) : rasterizer{rasterizer_}, - cpu_memory{cpu_memory_}, streams{{CounterStream{static_cast<QueryCache&>(*this), + // Use reinterpret_cast instead of static_cast as workaround for + // UBSan bug (https://github.com/llvm/llvm-project/issues/59060) + cpu_memory{cpu_memory_}, streams{{CounterStream{reinterpret_cast<QueryCache&>(*this), VideoCore::QueryType::SamplesPassed}}} { (void)slot_async_jobs.insert(); // Null value } |
