eden-emu/eden
14
3
Fork 4
Code Issues 3 Pull requests 2 Projects Releases 2 Packages Wiki Activity Actions

Fixes and workarounds to make UBSan happier on macOS

Browse source 
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.
This commit is contained in:
comex 2023-07-01 15:00:39 -07:00
parent 04868ab9da
commit d7c532d889
11 changed files with 42 additions and 32 deletions
Download patch file Download diff file Expand all files Collapse all files

30
src/core/memory.cpp
View file

@ -73,7 +73,7 @@ struct Memory::Impl {
return {};
}
return system.DeviceMemory().GetPointer<u8>(paddr) + vaddr;
return system.DeviceMemory().GetPointer<u8>(paddr + vaddr);
}
[[nodiscard]] u8* GetPointerFromDebugMemory(u64 vaddr) const {
@ -84,7 +84,7 @@ struct Memory::Impl {
return {};
}
return system.DeviceMemory().GetPointer<u8>(paddr) + vaddr;
return system.DeviceMemory().GetPointer<u8>(paddr + vaddr);
}
u8 Read8(const Common::ProcessAddress addr) {
@ -204,7 +204,8 @@ struct Memory::Impl {
break;
}
case Common::PageType::Memory: {
u8* mem_ptr = pointer + page_offset + (page_index << YUZU_PAGEBITS);
u8* mem_ptr =
reinterpret_cast<u8*>(pointer + page_offset + (page_index << YUZU_PAGEBITS));
on_memory(copy_amount, mem_ptr);
break;
}
@ -448,7 +449,7 @@ struct Memory::Impl {
break;
case Common::PageType::Memory:
current_page_table->pointers[vaddr >> YUZU_PAGEBITS].Store(
nullptr, Common::PageType::DebugMemory);
0, Common::PageType::DebugMemory);
break;
default:
UNREACHABLE();
@ -466,7 +467,8 @@ struct Memory::Impl {
case Common::PageType::DebugMemory: {
u8* const pointer{GetPointerFromDebugMemory(vaddr & ~YUZU_PAGEMASK)};
current_page_table->pointers[vaddr >> YUZU_PAGEBITS].Store(
pointer - (vaddr & ~YUZU_PAGEMASK), Common::PageType::Memory);
reinterpret_cast<uintptr_t>(pointer) - (vaddr & ~YUZU_PAGEMASK),
Common::PageType::Memory);
break;
}
default:
@ -506,7 +508,7 @@ struct Memory::Impl {
case Common::PageType::DebugMemory:
case Common::PageType::Memory:
current_page_table->pointers[vaddr >> YUZU_PAGEBITS].Store(
nullptr, Common::PageType::RasterizerCachedMemory);
0, Common::PageType::RasterizerCachedMemory);
break;
case Common::PageType::RasterizerCachedMemory:
// There can be more than one GPU region mapped per CPU region, so it's common
@ -534,10 +536,11 @@ struct Memory::Impl {
// pagetable after unmapping a VMA. In that case the underlying VMA will no
// longer exist, and we should just leave the pagetable entry blank.
current_page_table->pointers[vaddr >> YUZU_PAGEBITS].Store(
nullptr, Common::PageType::Unmapped);
0, Common::PageType::Unmapped);
} else {
current_page_table->pointers[vaddr >> YUZU_PAGEBITS].Store(
pointer - (vaddr & ~YUZU_PAGEMASK), Common::PageType::Memory);
reinterpret_cast<uintptr_t>(pointer) - (vaddr & ~YUZU_PAGEMASK),
Common::PageType::Memory);
}
break;
}
@ -584,7 +587,7 @@ struct Memory::Impl {
"Mapping memory page without a pointer @ {:016x}", base * YUZU_PAGESIZE);
while (base != end) {
page_table.pointers[base].Store(nullptr, type);
page_table.pointers[base].Store(0, type);
page_table.backing_addr[base] = 0;
page_table.blocks[base] = 0;
base += 1;
@ -593,7 +596,8 @@ struct Memory::Impl {
auto orig_base = base;
while (base != end) {
auto host_ptr =
system.DeviceMemory().GetPointer<u8>(target) - (base << YUZU_PAGEBITS);
reinterpret_cast<uintptr_t>(system.DeviceMemory().GetPointer<u8>(target)) -
(base << YUZU_PAGEBITS);
auto backing = GetInteger(target) - (base << YUZU_PAGEBITS);
page_table.pointers[base].Store(host_ptr, type);
page_table.backing_addr[base] = backing;
@ -619,8 +623,8 @@ struct Memory::Impl {
// Avoid adding any extra logic to this fast-path block
const uintptr_t raw_pointer = current_page_table->pointers[vaddr >> YUZU_PAGEBITS].Raw();
if (u8* const pointer = Common::PageTable::PageInfo::ExtractPointer(raw_pointer)) {
return &pointer[vaddr];
if (const uintptr_t pointer = Common::PageTable::PageInfo::ExtractPointer(raw_pointer)) {
return reinterpret_cast<u8*>(pointer + vaddr);
}
switch (Common::PageTable::PageInfo::ExtractType(raw_pointer)) {
case Common::PageType::Unmapped:
@ -814,7 +818,7 @@ bool Memory::IsValidVirtualAddress(const Common::ProcessAddress vaddr) const {
return false;
}
const auto [pointer, type] = page_table.pointers[page].PointerType();
return pointer != nullptr || type == Common::PageType::RasterizerCachedMemory ||
return pointer != 0 || type == Common::PageType::RasterizerCachedMemory ||
type == Common::PageType::DebugMemory;
}