RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 13:37:45 +00:00
Code Issues Activity Actions

Profiler: Fix disassembling objects with a non-zero .text vaddr

Browse source 
Previously, we assumed that the `.text` segment was loaded at vaddr 0 in
shared object, which is not the case with `-z separate-code` enabled.
Because we didn't do the right calculations to translate an address from
a performance event into its value within the ELF file, Profiler would
try to disassemble out-of-bounds memory locations, leading to a crash.

This commit also changes `LibraryMetadata` to apply to a loaded library
as a whole, not just to one of its segments (like .text or .data). This
lets us simplify the interface, as we no longer have to worry about
`text_base`.

Fixes #10628
This commit is contained in:
Daniel Bertalan 2021-10-25 11:20:30 +02:00 • committed by Andreas Kling
parent 15a14d3d21
commit ac1cac286b
2 changed files with 32 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

58
Userland/DevTools/Profiler/Process.cpp
View file

@ -68,36 +68,42 @@ static MappedObject* get_or_create_mapped_object(const String& path)
void LibraryMetadata::handle_mmap(FlatPtr base, size_t size, const String& name)
{
String path;
if (name.contains("Loader.so"))
path = "Loader.so";
else if (!name.contains(":"))
StringView path;
if (name.contains("Loader.so"sv))
path = "Loader.so"sv;
else if (!name.contains(':'))
return;
else
path = name.substring(0, name.view().find(':').value());
path = name.substring_view(0, name.view().find(':').value());
String full_path;
if (name.contains(".so"))
full_path = String::formatted("/usr/lib/{}", path);
else
full_path = path;
// Each loaded object has at least 4 segments associated with it: .rodata, .text, .relro, .data.
// We only want to create a single LibraryMetadata object for each library, so we need to update the
// associated base address and size as new regions are discovered.
auto* mapped_object = get_or_create_mapped_object(full_path);
if (!mapped_object) {
full_path = String::formatted("/usr/local/lib/{}", path);
mapped_object = get_or_create_mapped_object(full_path);
if (!mapped_object)
return;
// We don't allocate a temporary String object if an entry already exists.
// This assumes that String::hash and StringView::hash return the same result.
auto string_view_compare = [&path](auto& entry) { return path == entry.key.view(); };
if (auto existing_it = m_libraries.find(path.hash(), string_view_compare); existing_it != m_libraries.end()) {
auto& entry = *existing_it->value;
entry.base = min(entry.base, base);
entry.size = max(entry.size + size, base - entry.base + size);
} else {
String path_string = path.to_string();
String full_path;
if (name.contains(".so"sv))
full_path = String::formatted("/usr/lib/{}", path);
else
full_path = path_string;
auto* mapped_object = get_or_create_mapped_object(full_path);
if (!mapped_object) {
full_path = String::formatted("/usr/local/lib/{}", path);
mapped_object = get_or_create_mapped_object(full_path);
if (!mapped_object)
return;
}
m_libraries.set(path_string, adopt_own(*new Library { base, size, path_string, mapped_object }));
}
FlatPtr text_base {};
mapped_object->elf.for_each_program_header([&](const ELF::Image::ProgramHeader& ph) {
if (ph.is_executable())
text_base = ph.vaddr().get();
return IterationDecision::Continue;
});
m_libraries.set(name, adopt_own(*new Library { base, size, name, text_base, mapped_object }));
}
String LibraryMetadata::Library::symbolicate(FlatPtr ptr, u32* offset) const
@ -105,7 +111,7 @@ String LibraryMetadata::Library::symbolicate(FlatPtr ptr, u32* offset) const
if (!object)
return String::formatted("?? <{:p}>", ptr);
return object->elf.symbolicate(ptr - base + text_base, offset);
return object->elf.symbolicate(ptr - base, offset);
}
const LibraryMetadata::Library* LibraryMetadata::library_containing(FlatPtr ptr) const