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UserspaceEmulator: Exclude special ranges from RangeAllocator

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If we do not mark these ranges as reserved, RangeAllocator might later
give us addresses that overlap these, which then causes an assertion
failure in the SoftMMU.  This behavior led to recurring CI failures, and
sometimes made programs as simple as `/bin/true` fail.

Fixes "Crash 1" reported in #9104
This commit is contained in:
Daniel Bertalan 2021-12-24 22:54:26 +01:00 • committed by Idan Horowitz
parent 979f300337
commit 4e1898df99
4 changed files with 20 additions and 3 deletions
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10
Userland/DevTools/UserspaceEmulator/Emulator.cpp
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@ -34,6 +34,8 @@ namespace UserspaceEmulator {
static constexpr u32 stack_location = 0x10000000;
static constexpr size_t stack_size = 1 * MiB;
static constexpr u32 signal_trampoline_location = 0xb0000000;
static Emulator* s_the;
Emulator& Emulator::the()
@ -95,6 +97,7 @@ Vector<ELF::AuxiliaryValue> Emulator::generate_auxiliary_vector(FlatPtr load_bas
void Emulator::setup_stack(Vector<ELF::AuxiliaryValue> aux_vector)
{
m_range_allocator.reserve_user_range(VirtualAddress(stack_location), stack_size);
auto stack_region = make<SimpleRegion>(stack_location, stack_size);
stack_region->set_stack(true);
m_mmu.add_region(move(stack_region));
@ -183,7 +186,9 @@ bool Emulator::load_elf()
VERIFY(program_header.type() != PT_TLS);
if (program_header.type() == PT_LOAD) {
auto region = make<SimpleRegion>(program_header.vaddr().offset(interpreter_load_offset).get(), program_header.size_in_memory());
auto start_address = program_header.vaddr().offset(interpreter_load_offset);
m_range_allocator.reserve_user_range(start_address, program_header.size_in_memory());
auto region = make<SimpleRegion>(start_address.get(), program_header.size_in_memory());
if (program_header.is_executable() && !program_header.is_writable())
region->set_text(true);
memcpy(region->data(), program_header.raw_data(), program_header.size_in_image());
@ -666,7 +671,8 @@ extern "C" void asm_signal_trampoline_end(void);
void Emulator::setup_signal_trampoline()
{
auto trampoline_region = make<SimpleRegion>(0xb0000000, 4096);
m_range_allocator.reserve_user_range(VirtualAddress(signal_trampoline_location), 4096);
auto trampoline_region = make<SimpleRegion>(signal_trampoline_location, 4096);
u8* trampoline = (u8*)asm_signal_trampoline;
u8* trampoline_end = (u8*)asm_signal_trampoline_end;