diff options
| -rw-r--r-- | Kernel/Arch/i386/CPU.cpp | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/Kernel/Arch/i386/CPU.cpp b/Kernel/Arch/i386/CPU.cpp index d1a9ccb136..ca5425cffd 100644 --- a/Kernel/Arch/i386/CPU.cpp +++ b/Kernel/Arch/i386/CPU.cpp @@ -401,9 +401,23 @@ void page_fault_handler(TrapFrame* trap) dump(regs); #endif - bool faulted_in_userspace = (regs.cs & 3) == 3; + bool faulted_in_kernel = !(regs.cs & 3); + + if (faulted_in_kernel && Processor::current().in_irq()) { + // If we're faulting in an IRQ handler, first check if we failed + // due to safe_memcpy, safe_strnlen, or safe_memset. If we did, + // gracefully continue immediately. Because we're in an IRQ handler + // we can't really try to resolve the page fault in a meaningful + // way, so we need to do this before calling into + // MemoryManager::handle_page_fault, which would just bail and + // request a crash + if (handle_safe_access_fault(regs, fault_address)) + return; + } + + auto current_thread = Thread::current(); - if (faulted_in_userspace && !MM.validate_user_stack(current_thread->process(), VirtualAddress(regs.userspace_esp))) { + if (!faulted_in_kernel && !MM.validate_user_stack(current_thread->process(), VirtualAddress(regs.userspace_esp))) { dbg() << "Invalid stack pointer: " << VirtualAddress(regs.userspace_esp); handle_crash(regs, "Bad stack on page fault", SIGSTKFLT); ASSERT_NOT_REACHED(); @@ -412,7 +426,7 @@ void page_fault_handler(TrapFrame* trap) auto response = MM.handle_page_fault(PageFault(regs.exception_code, VirtualAddress(fault_address))); if (response == PageFaultResponse::ShouldCrash || response == PageFaultResponse::OutOfMemory) { - if (!(regs.cs & 3) && handle_safe_access_fault(regs, fault_address)) { + if (faulted_in_kernel && handle_safe_access_fault(regs, fault_address)) { // If this would be a ring0 (kernel) fault and the fault was triggered by // safe_memcpy, safe_strnlen, or safe_memset then we resume execution at // the appropriate _fault label rather than crashing |