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Kernel: Don't get rbp from internal context switch structures

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This has been broken on x86_64 since its introduction, as it features
more registers to be saved, and we never held up the "rbp has to be the
last pushed register" there.

Instead, just copy rbp from the thread structure, which is now properly
updated since the last commit.
This commit is contained in:
Tim Schumacher 2023-04-17 15:13:39 +02:00 • committed by Andreas Kling
parent 0ee476948b
commit aefd6e9ee1
Notes: sideshowbarker 2024-07-16 21:18:38 +09:00
1 changed files with 1 additions and 13 deletions
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14
Kernel/Arch/x86_64/Processor.cpp
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@ -863,23 +863,11 @@ ErrorOr<Vector<FlatPtr, 32>> Processor::capture_stack_trace(Thread& thread, size
case Thread::State::Blocked:
case Thread::State::Dying:
case Thread::State::Dead: {
// We need to retrieve ebp from what was last pushed to the kernel
// stack. Before switching out of that thread, it switch_context
// pushed the callee-saved registers, and the last of them happens
// to be ebp.
ScopedAddressSpaceSwitcher switcher(thread.process());
auto& regs = thread.regs();
auto* stack_top = reinterpret_cast<FlatPtr*>(regs.sp());
if (Memory::is_user_range(VirtualAddress(stack_top), sizeof(FlatPtr))) {
if (copy_from_user(&frame_ptr, &((FlatPtr*)stack_top)[0]).is_error())
frame_ptr = 0;
} else {
void* fault_at;
if (!safe_memcpy(&frame_ptr, &((FlatPtr*)stack_top)[0], sizeof(FlatPtr), fault_at))
frame_ptr = 0;
}
ip = regs.ip();
frame_ptr = regs.rbp;
// TODO: We need to leave the scheduler lock here, but we also
// need to prevent the target thread from being run while