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Kernel: Wrap process address spaces in SpinlockProtected

This forces anyone who wants to look into and/or manipulate an address
space to lock it. And this replaces the previous, more flimsy, manual
spinlock use.

Note that pointers *into* the address space are not safe to use after
you unlock the space. We've got many issues like this, and we'll have
to track those down as wlel.
This commit is contained in:
Andreas Kling 2022-08-23 17:58:05 +02:00
parent d6ef18f587
commit cf16b2c8e6
38 changed files with 708 additions and 627 deletions

View file

@ -46,17 +46,19 @@ Coredump::Coredump(NonnullLockRefPtr<Process> process, NonnullLockRefPtr<OpenFil
, m_description(move(description))
{
m_num_program_headers = 0;
m_process->address_space().region_tree().with([&](auto& region_tree) {
for (auto& region : region_tree.regions()) {
m_process->address_space().with([&](auto& space) {
space->region_tree().with([&](auto& region_tree) {
for (auto& region : region_tree.regions()) {
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(region))
continue;
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region.access() == Memory::Region::Access::None)
continue;
++m_num_program_headers;
}
if (region.access() == Memory::Region::Access::None)
continue;
++m_num_program_headers;
}
});
});
++m_num_program_headers; // +1 for NOTE segment
}
@ -135,38 +137,40 @@ ErrorOr<void> Coredump::write_elf_header()
ErrorOr<void> Coredump::write_program_headers(size_t notes_size)
{
size_t offset = sizeof(ElfW(Ehdr)) + m_num_program_headers * sizeof(ElfW(Phdr));
m_process->address_space().region_tree().with([&](auto& region_tree) {
for (auto& region : region_tree.regions()) {
m_process->address_space().with([&](auto& space) {
space->region_tree().with([&](auto& region_tree) {
for (auto& region : region_tree.regions()) {
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(region))
continue;
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region.access() == Memory::Region::Access::None)
continue;
if (region.access() == Memory::Region::Access::None)
continue;
ElfW(Phdr) phdr {};
ElfW(Phdr) phdr {};
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
phdr.p_vaddr = region.vaddr().get();
phdr.p_paddr = 0;
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
phdr.p_vaddr = region.vaddr().get();
phdr.p_paddr = 0;
phdr.p_filesz = region.page_count() * PAGE_SIZE;
phdr.p_memsz = region.page_count() * PAGE_SIZE;
phdr.p_align = 0;
phdr.p_filesz = region.page_count() * PAGE_SIZE;
phdr.p_memsz = region.page_count() * PAGE_SIZE;
phdr.p_align = 0;
phdr.p_flags = region.is_readable() ? PF_R : 0;
if (region.is_writable())
phdr.p_flags |= PF_W;
if (region.is_executable())
phdr.p_flags |= PF_X;
phdr.p_flags = region.is_readable() ? PF_R : 0;
if (region.is_writable())
phdr.p_flags |= PF_W;
if (region.is_executable())
phdr.p_flags |= PF_X;
offset += phdr.p_filesz;
offset += phdr.p_filesz;
[[maybe_unused]] auto rc = m_description->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&phdr)), sizeof(ElfW(Phdr)));
}
[[maybe_unused]] auto rc = m_description->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&phdr)), sizeof(ElfW(Phdr)));
}
});
});
ElfW(Phdr) notes_pheader {};
@ -188,37 +192,39 @@ ErrorOr<void> Coredump::write_regions()
{
u8 zero_buffer[PAGE_SIZE] = {};
return m_process->address_space().region_tree().with([&](auto& region_tree) -> ErrorOr<void> {
for (auto& region : region_tree.regions()) {
VERIFY(!region.is_kernel());
return m_process->address_space().with([&](auto& space) {
return space->region_tree().with([&](auto& region_tree) -> ErrorOr<void> {
for (auto& region : region_tree.regions()) {
VERIFY(!region.is_kernel());
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(region))
continue;
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region.access() == Memory::Region::Access::None)
continue;
if (region.access() == Memory::Region::Access::None)
continue;
// If we crashed in the middle of mapping in Regions, they do not have a page directory yet, and will crash on a remap() call
if (!region.is_mapped())
continue;
// If we crashed in the middle of mapping in Regions, they do not have a page directory yet, and will crash on a remap() call
if (!region.is_mapped())
continue;
region.set_readable(true);
region.remap();
region.set_readable(true);
region.remap();
for (size_t i = 0; i < region.page_count(); i++) {
auto page = region.physical_page(i);
auto src_buffer = [&]() -> ErrorOr<UserOrKernelBuffer> {
if (page)
return UserOrKernelBuffer::for_user_buffer(reinterpret_cast<uint8_t*>((region.vaddr().as_ptr() + (i * PAGE_SIZE))), PAGE_SIZE);
// If the current page is not backed by a physical page, we zero it in the coredump file.
return UserOrKernelBuffer::for_kernel_buffer(zero_buffer);
}();
TRY(m_description->write(src_buffer.value(), PAGE_SIZE));
for (size_t i = 0; i < region.page_count(); i++) {
auto page = region.physical_page(i);
auto src_buffer = [&]() -> ErrorOr<UserOrKernelBuffer> {
if (page)
return UserOrKernelBuffer::for_user_buffer(reinterpret_cast<uint8_t*>((region.vaddr().as_ptr() + (i * PAGE_SIZE))), PAGE_SIZE);
// If the current page is not backed by a physical page, we zero it in the coredump file.
return UserOrKernelBuffer::for_kernel_buffer(zero_buffer);
}();
TRY(m_description->write(src_buffer.value(), PAGE_SIZE));
}
}
}
return {};
return {};
});
});
}
@ -279,34 +285,36 @@ ErrorOr<void> Coredump::create_notes_threads_data(auto& builder) const
ErrorOr<void> Coredump::create_notes_regions_data(auto& builder) const
{
size_t region_index = 0;
return m_process->address_space().region_tree().with([&](auto& region_tree) -> ErrorOr<void> {
for (auto const& region : region_tree.regions()) {
return m_process->address_space().with([&](auto& space) {
return space->region_tree().with([&](auto& region_tree) -> ErrorOr<void> {
for (auto const& region : region_tree.regions()) {
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(region))
continue;
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region.access() == Memory::Region::Access::None)
continue;
if (region.access() == Memory::Region::Access::None)
continue;
ELF::Core::MemoryRegionInfo info {};
info.header.type = ELF::Core::NotesEntryHeader::Type::MemoryRegionInfo;
ELF::Core::MemoryRegionInfo info {};
info.header.type = ELF::Core::NotesEntryHeader::Type::MemoryRegionInfo;
info.region_start = region.vaddr().get();
info.region_end = region.vaddr().offset(region.size()).get();
info.program_header_index = region_index++;
info.region_start = region.vaddr().get();
info.region_end = region.vaddr().offset(region.size()).get();
info.program_header_index = region_index++;
TRY(builder.append_bytes(ReadonlyBytes { (void*)&info, sizeof(info) }));
TRY(builder.append_bytes(ReadonlyBytes { (void*)&info, sizeof(info) }));
// NOTE: The region name *is* null-terminated, so the following is ok:
auto name = region.name();
if (name.is_empty())
TRY(builder.append('\0'));
else
TRY(builder.append(name.characters_without_null_termination(), name.length() + 1));
}
return {};
// NOTE: The region name *is* null-terminated, so the following is ok:
auto name = region.name();
if (name.is_empty())
TRY(builder.append('\0'));
else
TRY(builder.append(name.characters_without_null_termination(), name.length() + 1));
}
return {};
});
});
}
@ -344,7 +352,6 @@ ErrorOr<void> Coredump::create_notes_segment_data(auto& builder) const
ErrorOr<void> Coredump::write()
{
SpinlockLocker lock(m_process->address_space().get_lock());
ScopedAddressSpaceSwitcher switcher(m_process);
auto builder = TRY(KBufferBuilder::try_create());