如何实现内核级线程的clone XV6

Question

在尝试测试我的克隆系统调用（下面的代码），我不断收到以下错误：

pid 4 thread_test: trap 13 err 0 on cpu 1 eip 0xc54 addr 0x0--kill proc pid 5 thread_test: trap 14 err 4 on cpu 1 eip 0x0 addr 0x28ec83e5--kill proc

对应于一般性保护错误和页面错误。有没有人知道什么可能导致新线程在创建后立即被杀死？

int clone(void *(*func) (void *), void *arg, void *stack) 
{ 
    int i,pid; 
    struct proc *np; 

    // Allocate process. 
    if((np = allocproc()) == 0) 
    return -1; 

    np->state = UNUSED; 
    np->sz = proc->sz; 
    np->parent = proc; 
    *np->tf = *proc->tf; 
    np->pgdir = proc->pgdir; 

    np->tf->eax = 0; // Clear %eax so that fork returns 0 in the child. 
    np->tf->eip = (int)func; //change eip to new function 
    np->kstack = stack; //use given stack 

    for(i = 0; i < NOFILE; i++) 
    if(proc->ofile[i]) 
     np->ofile[i] = filedup(proc->ofile[i]); 
    np->cwd = idup(proc->cwd); 

    np->tf->esp = (uint)(stack+PGSIZE-4); //put esp to right spot on stack 
    *((uint*)(np->tf->esp)) = (uint)arg; //arg to function 
    *((uint*)(np->tf->esp)-4) = 0xFFFFFFFF; //return to nowhere 
    np->tf->esp =(np->tf->esp) -4; 

    safestrcpy(np->name, proc->name, sizeof(proc->name)); 
    pid = np->pid; 

    acquire(&ptable.lock); //lock so writes last 
    np->state = RUNNABLE; 
    release(&ptable.lock); 

    return pid; 
} 

Answer 1

我找到了解决方案，我试图使用传入堆栈作为线程的kstack。我需要在proc.h创建一个单独的堆栈，然后使用分配堆栈线程：

np->stack = (int)stack;