Validate allocations against mappings
Bug 120032857 is seeing what appears to be allocations with incorrect
end addresses, leading to a much later crash when it tries to map
a zero page outside the valid virtual address space. Detect allocations
that extend outside the highest or lowest memory mapping and crash
immediately instead.
Test: memunreachable_test
Bug: 120032857
Change-Id: I9be670a025143e7078360a6bf7a83219279614d9
diff --git a/libmemunreachable/HeapWalker.cpp b/libmemunreachable/HeapWalker.cpp
index a046dad..89837f7 100644
--- a/libmemunreachable/HeapWalker.cpp
+++ b/libmemunreachable/HeapWalker.cpp
@@ -35,6 +35,13 @@
end = begin + 1;
}
Range range{begin, end};
+ if (valid_mappings_range_.end != 0 &&
+ (begin < valid_mappings_range_.begin || end > valid_mappings_range_.end)) {
+ MEM_LOG_ALWAYS_FATAL("allocation %p-%p is outside mapping range %p-%p",
+ reinterpret_cast<void*>(begin), reinterpret_cast<void*>(end),
+ reinterpret_cast<void*>(valid_mappings_range_.begin),
+ reinterpret_cast<void*>(valid_mappings_range_.end));
+ }
auto inserted = allocations_.insert(std::pair<Range, AllocationInfo>(range, AllocationInfo{}));
if (inserted.second) {
valid_allocations_range_.begin = std::min(valid_allocations_range_.begin, begin);
@@ -87,6 +94,11 @@
}
}
+void HeapWalker::Mapping(uintptr_t begin, uintptr_t end) {
+ valid_mappings_range_.begin = std::min(valid_mappings_range_.begin, begin);
+ valid_mappings_range_.end = std::max(valid_mappings_range_.end, end);
+}
+
void HeapWalker::Root(uintptr_t begin, uintptr_t end) {
roots_.push_back(Range{begin, end});
}