Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1274 insertions, 0 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
new file mode 100644
index 000000000000..f42a17f88699
--- /dev/null
+++ b/kernel/fork.c
@@ -0,0 +1,1274 @@
+/*
+ *  linux/kernel/fork.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+/*
+ *  'fork.c' contains the help-routines for the 'fork' system call
+ * (see also entry.S and others).
+ * Fork is rather simple, once you get the hang of it, but the memory
+ * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
+ */
+
+#include <linux/config.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/unistd.h>
+#include <linux/smp_lock.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/completion.h>
+#include <linux/namespace.h>
+#include <linux/personality.h>
+#include <linux/mempolicy.h>
+#include <linux/sem.h>
+#include <linux/file.h>
+#include <linux/key.h>
+#include <linux/binfmts.h>
+#include <linux/mman.h>
+#include <linux/fs.h>
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/security.h>
+#include <linux/swap.h>
+#include <linux/syscalls.h>
+#include <linux/jiffies.h>
+#include <linux/futex.h>
+#include <linux/ptrace.h>
+#include <linux/mount.h>
+#include <linux/audit.h>
+#include <linux/profile.h>
+#include <linux/rmap.h>
+#include <linux/acct.h>
+
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/uaccess.h>
+#include <asm/mmu_context.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+
+/*
+ * Protected counters by write_lock_irq(&tasklist_lock)
+ */
+unsigned long total_forks;      /* Handle normal Linux uptimes. */
+int nr_threads;                 /* The idle threads do not count.. */
+
+int max_threads;                /* tunable limit on nr_threads */
+
+DEFINE_PER_CPU(unsigned long, process_counts) = 0;
+
+ __cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */
+
+EXPORT_SYMBOL(tasklist_lock);
+
+int nr_processes(void)
+{
+        int cpu;
+        int total = 0;
+
+        for_each_online_cpu(cpu)
+                total += per_cpu(process_counts, cpu);
+
+        return total;
+}
+
+#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
+# define alloc_task_struct()    kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
+# define free_task_struct(tsk)  kmem_cache_free(task_struct_cachep, (tsk))
+static kmem_cache_t *task_struct_cachep;
+#endif
+
+/* SLAB cache for signal_struct structures (tsk->signal) */
+kmem_cache_t *signal_cachep;
+
+/* SLAB cache for sighand_struct structures (tsk->sighand) */
+kmem_cache_t *sighand_cachep;
+
+/* SLAB cache for files_struct structures (tsk->files) */
+kmem_cache_t *files_cachep;
+
+/* SLAB cache for fs_struct structures (tsk->fs) */
+kmem_cache_t *fs_cachep;
+
+/* SLAB cache for vm_area_struct structures */
+kmem_cache_t *vm_area_cachep;
+
+/* SLAB cache for mm_struct structures (tsk->mm) */
+static kmem_cache_t *mm_cachep;
+
+void free_task(struct task_struct *tsk)
+{
+        free_thread_info(tsk->thread_info);
+        free_task_struct(tsk);
+}
+EXPORT_SYMBOL(free_task);
+
+void __put_task_struct(struct task_struct *tsk)
+{
+        WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)));
+        WARN_ON(atomic_read(&tsk->usage));
+        WARN_ON(tsk == current);
+
+        if (unlikely(tsk->audit_context))
+                audit_free(tsk);
+        security_task_free(tsk);
+        free_uid(tsk->user);
+        put_group_info(tsk->group_info);
+
+        if (!profile_handoff_task(tsk))
+                free_task(tsk);
+}
+
+void __init fork_init(unsigned long mempages)
+{
+#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
+#ifndef ARCH_MIN_TASKALIGN
+#define ARCH_MIN_TASKALIGN      L1_CACHE_BYTES
+#endif
+        /* create a slab on which task_structs can be allocated */
+        task_struct_cachep =
+                kmem_cache_create("task_struct", sizeof(struct task_struct),
+                        ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL);
+#endif
+
+        /*
+         * The default maximum number of threads is set to a safe
+         * value: the thread structures can take up at most half
+         * of memory.
+         */
+        max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE);
+
+        /*
+         * we need to allow at least 20 threads to boot a system
+         */
+        if(max_threads < 20)
+                max_threads = 20;
+
+        init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
+        init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
+        init_task.signal->rlim[RLIMIT_SIGPENDING] =
+                init_task.signal->rlim[RLIMIT_NPROC];
+}
+
+static struct task_struct *dup_task_struct(struct task_struct *orig)
+{
+        struct task_struct *tsk;
+        struct thread_info *ti;
+
+        prepare_to_copy(orig);
+
+        tsk = alloc_task_struct();
+        if (!tsk)
+                return NULL;
+
+        ti = alloc_thread_info(tsk);
+        if (!ti) {
+                free_task_struct(tsk);
+                return NULL;
+        }
+
+        *ti = *orig->thread_info;
+        *tsk = *orig;
+        tsk->thread_info = ti;
+        ti->task = tsk;
+
+        /* One for us, one for whoever does the "release_task()" (usually parent) */
+        atomic_set(&tsk->usage,2);
+        return tsk;
+}
+
+#ifdef CONFIG_MMU
+static inline int dup_mmap(struct mm_struct * mm, struct mm_struct * oldmm)
+{
+        struct vm_area_struct * mpnt, *tmp, **pprev;
+        struct rb_node **rb_link, *rb_parent;
+        int retval;
+        unsigned long charge;
+        struct mempolicy *pol;
+
+        down_write(&oldmm->mmap_sem);
+        flush_cache_mm(current->mm);
+        mm->locked_vm = 0;
+        mm->mmap = NULL;
+        mm->mmap_cache = NULL;
+        mm->free_area_cache = oldmm->mmap_base;
+        mm->map_count = 0;
+        set_mm_counter(mm, rss, 0);
+        set_mm_counter(mm, anon_rss, 0);
+        cpus_clear(mm->cpu_vm_mask);
+        mm->mm_rb = RB_ROOT;
+        rb_link = &mm->mm_rb.rb_node;
+        rb_parent = NULL;
+        pprev = &mm->mmap;
+
+        for (mpnt = current->mm->mmap ; mpnt ; mpnt = mpnt->vm_next) {
+                struct file *file;
+
+                if (mpnt->vm_flags & VM_DONTCOPY) {
+                        __vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file,
+                                                        -vma_pages(mpnt));
+                        continue;
+                }
+                charge = 0;
+                if (mpnt->vm_flags & VM_ACCOUNT) {
+                        unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
+                        if (security_vm_enough_memory(len))
+                                goto fail_nomem;
+                        charge = len;
+                }
+                tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+                if (!tmp)
+                        goto fail_nomem;
+                *tmp = *mpnt;
+                pol = mpol_copy(vma_policy(mpnt));
+                retval = PTR_ERR(pol);
+                if (IS_ERR(pol))
+                        goto fail_nomem_policy;
+                vma_set_policy(tmp, pol);
+                tmp->vm_flags &= ~VM_LOCKED;
+                tmp->vm_mm = mm;
+                tmp->vm_next = NULL;
+                anon_vma_link(tmp);
+                file = tmp->vm_file;
+                if (file) {
+                        struct inode *inode = file->f_dentry->d_inode;
+                        get_file(file);
+                        if (tmp->vm_flags & VM_DENYWRITE)
+                                atomic_dec(&inode->i_writecount);
+      
+                        /* insert tmp into the share list, just after mpnt */
+                        spin_lock(&file->f_mapping->i_mmap_lock);
+                        tmp->vm_truncate_count = mpnt->vm_truncate_count;
+                        flush_dcache_mmap_lock(file->f_mapping);
+                        vma_prio_tree_add(tmp, mpnt);
+                        flush_dcache_mmap_unlock(file->f_mapping);
+                        spin_unlock(&file->f_mapping->i_mmap_lock);
+                }
+
+                /*
+                 * Link in the new vma and copy the page table entries:
+                 * link in first so that swapoff can see swap entries,
+                 * and try_to_unmap_one's find_vma find the new vma.
+                 */
+                spin_lock(&mm->page_table_lock);
+                *pprev = tmp;
+                pprev = &tmp->vm_next;
+
+                __vma_link_rb(mm, tmp, rb_link, rb_parent);
+                rb_link = &tmp->vm_rb.rb_right;
+                rb_parent = &tmp->vm_rb;
+
+                mm->map_count++;
+                retval = copy_page_range(mm, current->mm, tmp);
+                spin_unlock(&mm->page_table_lock);
+
+                if (tmp->vm_ops && tmp->vm_ops->open)
+                        tmp->vm_ops->open(tmp);
+
+                if (retval)
+                        goto out;
+        }
+        retval = 0;
+
+out:
+        flush_tlb_mm(current->mm);
+        up_write(&oldmm->mmap_sem);
+        return retval;
+fail_nomem_policy:
+        kmem_cache_free(vm_area_cachep, tmp);
+fail_nomem:
+        retval = -ENOMEM;
+        vm_unacct_memory(charge);
+        goto out;
+}
+
+static inline int mm_alloc_pgd(struct mm_struct * mm)
+{
+        mm->pgd = pgd_alloc(mm);
+        if (unlikely(!mm->pgd))
+                return -ENOMEM;
+        return 0;
+}
+
+static inline void mm_free_pgd(struct mm_struct * mm)
+{
+        pgd_free(mm->pgd);
+}
+#else
+#define dup_mmap(mm, oldmm)     (0)
+#define mm_alloc_pgd(mm)        (0)
+#define mm_free_pgd(mm)
+#endif /* CONFIG_MMU */
+
+ __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
+
+#define allocate_mm()   (kmem_cache_alloc(mm_cachep, SLAB_KERNEL))
+#define free_mm(mm)     (kmem_cache_free(mm_cachep, (mm)))
+
+#include <linux/init_task.h>
+
+static struct mm_struct * mm_init(struct mm_struct * mm)
+{
+        atomic_set(&mm->mm_users, 1);
+        atomic_set(&mm->mm_count, 1);
+        init_rwsem(&mm->mmap_sem);
+        INIT_LIST_HEAD(&mm->mmlist);
+        mm->core_waiters = 0;
+        mm->nr_ptes = 0;
+        spin_lock_init(&mm->page_table_lock);
+        rwlock_init(&mm->ioctx_list_lock);
+        mm->ioctx_list = NULL;
+        mm->default_kioctx = (struct kioctx)INIT_KIOCTX(mm->default_kioctx, *mm);
+        mm->free_area_cache = TASK_UNMAPPED_BASE;
+
+        if (likely(!mm_alloc_pgd(mm))) {
+                mm->def_flags = 0;
+                return mm;
+        }
+        free_mm(mm);
+        return NULL;
+}
+
+/*
+ * Allocate and initialize an mm_struct.
+ */
+struct mm_struct * mm_alloc(void)
+{
+        struct mm_struct * mm;
+
+        mm = allocate_mm();
+        if (mm) {
+                memset(mm, 0, sizeof(*mm));
+                mm = mm_init(mm);
+        }
+        return mm;
+}
+
+/*
+ * Called when the last reference to the mm
+ * is dropped: either by a lazy thread or by
+ * mmput. Free the page directory and the mm.
+ */
+void fastcall __mmdrop(struct mm_struct *mm)
+{
+        BUG_ON(mm == &init_mm);
+        mm_free_pgd(mm);
+        destroy_context(mm);
+        free_mm(mm);
+}
+
+/*
+ * Decrement the use count and release all resources for an mm.
+ */
+void mmput(struct mm_struct *mm)
+{
+        if (atomic_dec_and_test(&mm->mm_users)) {
+                exit_aio(mm);
+                exit_mmap(mm);
+                if (!list_empty(&mm->mmlist)) {
+                        spin_lock(&mmlist_lock);
+                        list_del(&mm->mmlist);
+                        spin_unlock(&mmlist_lock);
+                }
+                put_swap_token(mm);
+                mmdrop(mm);
+        }
+}
+EXPORT_SYMBOL_GPL(mmput);
+
+/**
+ * get_task_mm - acquire a reference to the task's mm
+ *
+ * Returns %NULL if the task has no mm.  Checks PF_BORROWED_MM (meaning
+ * this kernel workthread has transiently adopted a user mm with use_mm,
+ * to do its AIO) is not set and if so returns a reference to it, after
+ * bumping up the use count.  User must release the mm via mmput()
+ * after use.  Typically used by /proc and ptrace.
+ */
+struct mm_struct *get_task_mm(struct task_struct *task)
+{
+        struct mm_struct *mm;
+
+        task_lock(task);
+        mm = task->mm;
+        if (mm) {
+                if (task->flags & PF_BORROWED_MM)
+                        mm = NULL;
+                else
+                        atomic_inc(&mm->mm_users);
+        }
+        task_unlock(task);
+        return mm;
+}
+EXPORT_SYMBOL_GPL(get_task_mm);
+
+/* Please note the differences between mmput and mm_release.
+ * mmput is called whenever we stop holding onto a mm_struct,
+ * error success whatever.
+ *
+ * mm_release is called after a mm_struct has been removed
+ * from the current process.
+ *
+ * This difference is important for error handling, when we
+ * only half set up a mm_struct for a new process and need to restore
+ * the old one.  Because we mmput the new mm_struct before
+ * restoring the old one. . .
+ * Eric Biederman 10 January 1998
+ */
+void mm_release(struct task_struct *tsk, struct mm_struct *mm)
+{
+        struct completion *vfork_done = tsk->vfork_done;
+
+        /* Get rid of any cached register state */
+        deactivate_mm(tsk, mm);
+
+        /* notify parent sleeping on vfork() */
+        if (vfork_done) {
+                tsk->vfork_done = NULL;
+                complete(vfork_done);
+        }
+        if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) {
+                u32 __user * tidptr = tsk->clear_child_tid;
+                tsk->clear_child_tid = NULL;
+
+                /*
+                 * We don't check the error code - if userspace has
+                 * not set up a proper pointer then tough luck.
+                 */
+                put_user(0, tidptr);
+                sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0);
+        }
+}
+
+static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
+{
+        struct mm_struct * mm, *oldmm;
+        int retval;
+
+        tsk->min_flt = tsk->maj_flt = 0;
+        tsk->nvcsw = tsk->nivcsw = 0;
+
+        tsk->mm = NULL;
+        tsk->active_mm = NULL;
+
+        /*
+         * Are we cloning a kernel thread?
+         *
+         * We need to steal a active VM for that..
+         */
+        oldmm = current->mm;
+        if (!oldmm)
+                return 0;
+
+        if (clone_flags & CLONE_VM) {
+                atomic_inc(&oldmm->mm_users);
+                mm = oldmm;
+                /*
+                 * There are cases where the PTL is held to ensure no
+                 * new threads start up in user mode using an mm, which
+                 * allows optimizing out ipis; the tlb_gather_mmu code
+                 * is an example.
+                 */
+                spin_unlock_wait(&oldmm->page_table_lock);
+                goto good_mm;
+        }
+
+        retval = -ENOMEM;
+        mm = allocate_mm();
+        if (!mm)
+                goto fail_nomem;
+
+        /* Copy the current MM stuff.. */
+        memcpy(mm, oldmm, sizeof(*mm));
+        if (!mm_init(mm))
+                goto fail_nomem;
+
+        if (init_new_context(tsk,mm))
+                goto fail_nocontext;
+
+        retval = dup_mmap(mm, oldmm);
+        if (retval)
+                goto free_pt;
+
+        mm->hiwater_rss = get_mm_counter(mm,rss);
+        mm->hiwater_vm = mm->total_vm;
+
+good_mm:
+        tsk->mm = mm;
+        tsk->active_mm = mm;
+        return 0;
+
+free_pt:
+        mmput(mm);
+fail_nomem:
+        return retval;
+
+fail_nocontext:
+        /*
+         * If init_new_context() failed, we cannot use mmput() to free the mm
+         * because it calls destroy_context()
+         */
+        mm_free_pgd(mm);
+        free_mm(mm);
+        return retval;
+}
+
+static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
+{
+        struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
+        /* We don't need to lock fs - think why ;-) */
+        if (fs) {
+                atomic_set(&fs->count, 1);
+                rwlock_init(&fs->lock);
+                fs->umask = old->umask;
+                read_lock(&old->lock);
+                fs->rootmnt = mntget(old->rootmnt);
+                fs->root = dget(old->root);
+                fs->pwdmnt = mntget(old->pwdmnt);
+                fs->pwd = dget(old->pwd);
+                if (old->altroot) {
+                        fs->altrootmnt = mntget(old->altrootmnt);
+                        fs->altroot = dget(old->altroot);
+                } else {
+                        fs->altrootmnt = NULL;
+                        fs->altroot = NULL;
+                }
+                read_unlock(&old->lock);
+        }
+        return fs;
+}
+
+struct fs_struct *copy_fs_struct(struct fs_struct *old)
+{
+        return __copy_fs_struct(old);
+}
+
+EXPORT_SYMBOL_GPL(copy_fs_struct);
+
+static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
+{
+        if (clone_flags & CLONE_FS) {
+                atomic_inc(&current->fs->count);
+                return 0;
+        }
+        tsk->fs = __copy_fs_struct(current->fs);
+        if (!tsk->fs)
+                return -ENOMEM;
+        return 0;
+}
+
+static int count_open_files(struct files_struct *files, int size)
+{
+        int i;
+
+        /* Find the last open fd */
+        for (i = size/(8*sizeof(long)); i > 0; ) {
+                if (files->open_fds->fds_bits[--i])
+                        break;
+        }
+        i = (i+1) * 8 * sizeof(long);
+        return i;
+}
+
+static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
+{
+        struct files_struct *oldf, *newf;
+        struct file **old_fds, **new_fds;
+        int open_files, size, i, error = 0, expand;
+
+        /*
+         * A background process may not have any files ...
+         */
+        oldf = current->files;
+        if (!oldf)
+                goto out;
+
+        if (clone_flags & CLONE_FILES) {
+                atomic_inc(&oldf->count);
+                goto out;
+        }
+
+        /*
+         * Note: we may be using current for both targets (See exec.c)
+         * This works because we cache current->files (old) as oldf. Don't
+         * break this.
+         */
+        tsk->files = NULL;
+        error = -ENOMEM;
+        newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL);
+        if (!newf) 
+                goto out;
+
+        atomic_set(&newf->count, 1);
+
+        spin_lock_init(&newf->file_lock);
+        newf->next_fd       = 0;
+        newf->max_fds       = NR_OPEN_DEFAULT;
+        newf->max_fdset     = __FD_SETSIZE;
+        newf->close_on_exec = &newf->close_on_exec_init;
+        newf->open_fds      = &newf->open_fds_init;
+        newf->fd            = &newf->fd_array[0];
+
+        spin_lock(&oldf->file_lock);
+
+        open_files = count_open_files(oldf, oldf->max_fdset);
+        expand = 0;
+
+        /*
+         * Check whether we need to allocate a larger fd array or fd set.
+         * Note: we're not a clone task, so the open count won't  change.
+         */
+        if (open_files > newf->max_fdset) {
+                newf->max_fdset = 0;
+                expand = 1;
+        }
+        if (open_files > newf->max_fds) {
+                newf->max_fds = 0;
+                expand = 1;
+        }
+
+        /* if the old fdset gets grown now, we'll only copy up to "size" fds */
+        if (expand) {
+                spin_unlock(&oldf->file_lock);
+                spin_lock(&newf->file_lock);
+                error = expand_files(newf, open_files-1);
+                spin_unlock(&newf->file_lock);
+                if (error < 0)
+                        goto out_release;
+                spin_lock(&oldf->file_lock);
+        }
+
+        old_fds = oldf->fd;
+        new_fds = newf->fd;
+
+        memcpy(newf->open_fds->fds_bits, oldf->open_fds->fds_bits, open_files/8);
+        memcpy(newf->close_on_exec->fds_bits, oldf->close_on_exec->fds_bits, open_files/8);
+
+        for (i = open_files; i != 0; i--) {
+                struct file *f = *old_fds++;
+                if (f) {
+                        get_file(f);
+                } else {
+                        /*
+                         * The fd may be claimed in the fd bitmap but not yet
+                         * instantiated in the files array if a sibling thread
+                         * is partway through open().  So make sure that this
+                         * fd is available to the new process.
+                         */
+                        FD_CLR(open_files - i, newf->open_fds);
+                }
+                *new_fds++ = f;
+        }
+        spin_unlock(&oldf->file_lock);
+
+        /* compute the remainder to be cleared */
+        size = (newf->max_fds - open_files) * sizeof(struct file *);
+
+        /* This is long word aligned thus could use a optimized version */ 
+        memset(new_fds, 0, size); 
+
+        if (newf->max_fdset > open_files) {
+                int left = (newf->max_fdset-open_files)/8;
+                int start = open_files / (8 * sizeof(unsigned long));
+
+                memset(&newf->open_fds->fds_bits[start], 0, left);
+                memset(&newf->close_on_exec->fds_bits[start], 0, left);
+        }
+
+        tsk->files = newf;
+        error = 0;
+out:
+        return error;
+
+out_release:
+        free_fdset (newf->close_on_exec, newf->max_fdset);
+        free_fdset (newf->open_fds, newf->max_fdset);
+        free_fd_array(newf->fd, newf->max_fds);
+        kmem_cache_free(files_cachep, newf);
+        goto out;
+}
+
+/*
+ *      Helper to unshare the files of the current task.
+ *      We don't want to expose copy_files internals to
+ *      the exec layer of the kernel.
+ */
+
+int unshare_files(void)
+{
+        struct files_struct *files  = current->files;
+        int rc;
+
+        if(!files)
+                BUG();
+
+        /* This can race but the race causes us to copy when we don't
+           need to and drop the copy */
+        if(atomic_read(&files->count) == 1)
+        {
+                atomic_inc(&files->count);
+                return 0;
+        }
+        rc = copy_files(0, current);
+        if(rc)
+                current->files = files;
+        return rc;
+}
+
+EXPORT_SYMBOL(unshare_files);
+
+static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
+{
+        struct sighand_struct *sig;
+
+        if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) {
+                atomic_inc(&current->sighand->count);
+                return 0;
+        }
+        sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
+        tsk->sighand = sig;
+        if (!sig)
+                return -ENOMEM;
+        spin_lock_init(&sig->siglock);
+        atomic_set(&sig->count, 1);
+        memcpy(sig->action, current->sighand->action, sizeof(sig->action));
+        return 0;
+}
+
+static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk)
+{
+        struct signal_struct *sig;
+        int ret;
+
+        if (clone_flags & CLONE_THREAD) {
+                atomic_inc(&current->signal->count);
+                atomic_inc(&current->signal->live);
+                return 0;
+        }
+        sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
+        tsk->signal = sig;
+        if (!sig)
+                return -ENOMEM;
+
+        ret = copy_thread_group_keys(tsk);
+        if (ret < 0) {
+                kmem_cache_free(signal_cachep, sig);
+                return ret;
+        }
+
+        atomic_set(&sig->count, 1);
+        atomic_set(&sig->live, 1);
+        init_waitqueue_head(&sig->wait_chldexit);
+        sig->flags = 0;
+        sig->group_exit_code = 0;
+        sig->group_exit_task = NULL;
+        sig->group_stop_count = 0;
+        sig->curr_target = NULL;
+        init_sigpending(&sig->shared_pending);
+        INIT_LIST_HEAD(&sig->posix_timers);
+
+        sig->it_real_value = sig->it_real_incr = 0;
+        sig->real_timer.function = it_real_fn;
+        sig->real_timer.data = (unsigned long) tsk;
+        init_timer(&sig->real_timer);
+
+        sig->it_virt_expires = cputime_zero;
+        sig->it_virt_incr = cputime_zero;
+        sig->it_prof_expires = cputime_zero;
+        sig->it_prof_incr = cputime_zero;
+
+        sig->tty = current->signal->tty;
+        sig->pgrp = process_group(current);
+        sig->session = current->signal->session;
+        sig->leader = 0;        /* session leadership doesn't inherit */
+        sig->tty_old_pgrp = 0;
+
+        sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero;
+        sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0;
+        sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0;
+        sig->sched_time = 0;
+        INIT_LIST_HEAD(&sig->cpu_timers[0]);
+        INIT_LIST_HEAD(&sig->cpu_timers[1]);
+        INIT_LIST_HEAD(&sig->cpu_timers[2]);
+
+        task_lock(current->group_leader);
+        memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
+        task_unlock(current->group_leader);
+
+        if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
+                /*
+                 * New sole thread in the process gets an expiry time
+                 * of the whole CPU time limit.
+                 */
+                tsk->it_prof_expires =
+                        secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
+        }
+
+        return 0;
+}
+
+static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
+{
+        unsigned long new_flags = p->flags;
+
+        new_flags &= ~PF_SUPERPRIV;
+        new_flags |= PF_FORKNOEXEC;
+        if (!(clone_flags & CLONE_PTRACE))
+                p->ptrace = 0;
+        p->flags = new_flags;
+}
+
+asmlinkage long sys_set_tid_address(int __user *tidptr)
+{
+        current->clear_child_tid = tidptr;
+
+        return current->pid;
+}
+
+/*
+ * This creates a new process as a copy of the old one,
+ * but does not actually start it yet.
+ *
+ * It copies the registers, and all the appropriate
+ * parts of the process environment (as per the clone
+ * flags). The actual kick-off is left to the caller.
+ */
+static task_t *copy_process(unsigned long clone_flags,
+                                 unsigned long stack_start,
+                                 struct pt_regs *regs,
+                                 unsigned long stack_size,
+                                 int __user *parent_tidptr,
+                                 int __user *child_tidptr,
+                                 int pid)
+{
+        int retval;
+        struct task_struct *p = NULL;
+
+        if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
+                return ERR_PTR(-EINVAL);
+
+        /*
+         * Thread groups must share signals as well, and detached threads
+         * can only be started up within the thread group.
+         */
+        if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
+                return ERR_PTR(-EINVAL);
+
+        /*
+         * Shared signal handlers imply shared VM. By way of the above,
+         * thread groups also imply shared VM. Blocking this case allows
+         * for various simplifications in other code.
+         */
+        if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
+                return ERR_PTR(-EINVAL);
+
+        retval = security_task_create(clone_flags);
+        if (retval)
+                goto fork_out;
+
+        retval = -ENOMEM;
+        p = dup_task_struct(current);
+        if (!p)
+                goto fork_out;
+
+        retval = -EAGAIN;
+        if (atomic_read(&p->user->processes) >=
+                        p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
+                if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
+                                p->user != &root_user)
+                        goto bad_fork_free;
+        }
+
+        atomic_inc(&p->user->__count);
+        atomic_inc(&p->user->processes);
+        get_group_info(p->group_info);
+
+        /*
+         * If multiple threads are within copy_process(), then this check
+         * triggers too late. This doesn't hurt, the check is only there
+         * to stop root fork bombs.
+         */
+        if (nr_threads >= max_threads)
+                goto bad_fork_cleanup_count;
+
+        if (!try_module_get(p->thread_info->exec_domain->module))
+                goto bad_fork_cleanup_count;
+
+        if (p->binfmt && !try_module_get(p->binfmt->module))
+                goto bad_fork_cleanup_put_domain;
+
+        p->did_exec = 0;
+        copy_flags(clone_flags, p);
+        p->pid = pid;
+        retval = -EFAULT;
+        if (clone_flags & CLONE_PARENT_SETTID)
+                if (put_user(p->pid, parent_tidptr))
+                        goto bad_fork_cleanup;
+
+        p->proc_dentry = NULL;
+
+        INIT_LIST_HEAD(&p->children);
+        INIT_LIST_HEAD(&p->sibling);
+        p->vfork_done = NULL;
+        spin_lock_init(&p->alloc_lock);
+        spin_lock_init(&p->proc_lock);
+
+        clear_tsk_thread_flag(p, TIF_SIGPENDING);
+        init_sigpending(&p->pending);
+
+        p->utime = cputime_zero;
+        p->stime = cputime_zero;
+        p->sched_time = 0;
+        p->rchar = 0;           /* I/O counter: bytes read */
+        p->wchar = 0;           /* I/O counter: bytes written */
+        p->syscr = 0;           /* I/O counter: read syscalls */
+        p->syscw = 0;           /* I/O counter: write syscalls */
+        acct_clear_integrals(p);
+
+        p->it_virt_expires = cputime_zero;
+        p->it_prof_expires = cputime_zero;
+        p->it_sched_expires = 0;
+        INIT_LIST_HEAD(&p->cpu_timers[0]);
+        INIT_LIST_HEAD(&p->cpu_timers[1]);
+        INIT_LIST_HEAD(&p->cpu_timers[2]);
+
+        p->lock_depth = -1;             /* -1 = no lock */
+        do_posix_clock_monotonic_gettime(&p->start_time);
+        p->security = NULL;
+        p->io_context = NULL;
+        p->io_wait = NULL;
+        p->audit_context = NULL;
+#ifdef CONFIG_NUMA
+        p->mempolicy = mpol_copy(p->mempolicy);
+        if (IS_ERR(p->mempolicy)) {
+                retval = PTR_ERR(p->mempolicy);
+                p->mempolicy = NULL;
+                goto bad_fork_cleanup;
+        }
+#endif
+
+        p->tgid = p->pid;
+        if (clone_flags & CLONE_THREAD)
+                p->tgid = current->tgid;
+
+        if ((retval = security_task_alloc(p)))
+                goto bad_fork_cleanup_policy;
+        if ((retval = audit_alloc(p)))
+                goto bad_fork_cleanup_security;
+        /* copy all the process information */
+        if ((retval = copy_semundo(clone_flags, p)))
+                goto bad_fork_cleanup_audit;
+        if ((retval = copy_files(clone_flags, p)))
+                goto bad_fork_cleanup_semundo;
+        if ((retval = copy_fs(clone_flags, p)))
+                goto bad_fork_cleanup_files;
+        if ((retval = copy_sighand(clone_flags, p)))
+                goto bad_fork_cleanup_fs;
+        if ((retval = copy_signal(clone_flags, p)))
+                goto bad_fork_cleanup_sighand;
+        if ((retval = copy_mm(clone_flags, p)))
+                goto bad_fork_cleanup_signal;
+        if ((retval = copy_keys(clone_flags, p)))
+                goto bad_fork_cleanup_mm;
+        if ((retval = copy_namespace(clone_flags, p)))
+                goto bad_fork_cleanup_keys;
+        retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
+        if (retval)
+                goto bad_fork_cleanup_namespace;
+
+        p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
+        /*
+         * Clear TID on mm_release()?
+         */
+        p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
+
+        /*
+         * Syscall tracing should be turned off in the child regardless
+         * of CLONE_PTRACE.
+         */
+        clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
+
+        /* Our parent execution domain becomes current domain
+           These must match for thread signalling to apply */
+           
+        p->parent_exec_id = p->self_exec_id;
+
+        /* ok, now we should be set up.. */
+        p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
+        p->pdeath_signal = 0;
+        p->exit_state = 0;
+
+        /* Perform scheduler related setup */
+        sched_fork(p);
+
+        /*
+         * Ok, make it visible to the rest of the system.
+         * We dont wake it up yet.
+         */
+        p->group_leader = p;
+        INIT_LIST_HEAD(&p->ptrace_children);
+        INIT_LIST_HEAD(&p->ptrace_list);
+
+        /* Need tasklist lock for parent etc handling! */
+        write_lock_irq(&tasklist_lock);
+
+        /*
+         * The task hasn't been attached yet, so cpus_allowed mask cannot
+         * have changed. The cpus_allowed mask of the parent may have
+         * changed after it was copied first time, and it may then move to
+         * another CPU - so we re-copy it here and set the child's CPU to
+         * the parent's CPU. This avoids alot of nasty races.
+         */
+        p->cpus_allowed = current->cpus_allowed;
+        set_task_cpu(p, smp_processor_id());
+
+        /*
+         * Check for pending SIGKILL! The new thread should not be allowed
+         * to slip out of an OOM kill. (or normal SIGKILL.)
+         */
+        if (sigismember(&current->pending.signal, SIGKILL)) {
+                write_unlock_irq(&tasklist_lock);
+                retval = -EINTR;
+                goto bad_fork_cleanup_namespace;
+        }
+
+        /* CLONE_PARENT re-uses the old parent */
+        if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
+                p->real_parent = current->real_parent;
+        else
+                p->real_parent = current;
+        p->parent = p->real_parent;
+
+        if (clone_flags & CLONE_THREAD) {
+                spin_lock(&current->sighand->siglock);
+                /*
+                 * Important: if an exit-all has been started then
+                 * do not create this new thread - the whole thread
+                 * group is supposed to exit anyway.
+                 */
+                if (current->signal->flags & SIGNAL_GROUP_EXIT) {
+                        spin_unlock(&current->sighand->siglock);
+                        write_unlock_irq(&tasklist_lock);
+                        retval = -EAGAIN;
+                        goto bad_fork_cleanup_namespace;
+                }
+                p->group_leader = current->group_leader;
+
+                if (current->signal->group_stop_count > 0) {
+                        /*
+                         * There is an all-stop in progress for the group.
+                         * We ourselves will stop as soon as we check signals.
+                         * Make the new thread part of that group stop too.
+                         */
+                        current->signal->group_stop_count++;
+                        set_tsk_thread_flag(p, TIF_SIGPENDING);
+                }
+
+                if (!cputime_eq(current->signal->it_virt_expires,
+                                cputime_zero) ||
+                    !cputime_eq(current->signal->it_prof_expires,
+                                cputime_zero) ||
+                    current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY ||
+                    !list_empty(&current->signal->cpu_timers[0]) ||
+                    !list_empty(&current->signal->cpu_timers[1]) ||
+                    !list_empty(&current->signal->cpu_timers[2])) {
+                        /*
+                         * Have child wake up on its first tick to check
+                         * for process CPU timers.
+                         */
+                        p->it_prof_expires = jiffies_to_cputime(1);
+                }
+
+                spin_unlock(&current->sighand->siglock);
+        }
+
+        SET_LINKS(p);
+        if (unlikely(p->ptrace & PT_PTRACED))
+                __ptrace_link(p, current->parent);
+
+        cpuset_fork(p);
+
+        attach_pid(p, PIDTYPE_PID, p->pid);
+        attach_pid(p, PIDTYPE_TGID, p->tgid);
+        if (thread_group_leader(p)) {
+                attach_pid(p, PIDTYPE_PGID, process_group(p));
+                attach_pid(p, PIDTYPE_SID, p->signal->session);
+                if (p->pid)
+                        __get_cpu_var(process_counts)++;
+        }
+
+        nr_threads++;
+        total_forks++;
+        write_unlock_irq(&tasklist_lock);
+        retval = 0;
+
+fork_out:
+        if (retval)
+                return ERR_PTR(retval);
+        return p;
+
+bad_fork_cleanup_namespace:
+        exit_namespace(p);
+bad_fork_cleanup_keys:
+        exit_keys(p);
+bad_fork_cleanup_mm:
+        if (p->mm)
+                mmput(p->mm);
+bad_fork_cleanup_signal:
+        exit_signal(p);
+bad_fork_cleanup_sighand:
+        exit_sighand(p);
+bad_fork_cleanup_fs:
+        exit_fs(p); /* blocking */
+bad_fork_cleanup_files:
+        exit_files(p); /* blocking */
+bad_fork_cleanup_semundo:
+        exit_sem(p);
+bad_fork_cleanup_audit:
+        audit_free(p);
+bad_fork_cleanup_security:
+        security_task_free(p);
+bad_fork_cleanup_policy:
+#ifdef CONFIG_NUMA
+        mpol_free(p->mempolicy);
+#endif
+bad_fork_cleanup:
+        if (p->binfmt)
+                module_put(p->binfmt->module);
+bad_fork_cleanup_put_domain:
+        module_put(p->thread_info->exec_domain->module);
+bad_fork_cleanup_count:
+        put_group_info(p->group_info);
+        atomic_dec(&p->user->processes);
+        free_uid(p->user);
+bad_fork_free:
+        free_task(p);
+        goto fork_out;
+}
+
+struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
+{
+        memset(regs, 0, sizeof(struct pt_regs));
+        return regs;
+}
+
+task_t * __devinit fork_idle(int cpu)
+{
+        task_t *task;
+        struct pt_regs regs;
+
+        task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL, NULL, 0);
+        if (!task)
+                return ERR_PTR(-ENOMEM);
+        init_idle(task, cpu);
+        unhash_process(task);
+        return task;
+}
+
+static inline int fork_traceflag (unsigned clone_flags)
+{
+        if (clone_flags & CLONE_UNTRACED)
+                return 0;
+        else if (clone_flags & CLONE_VFORK) {
+                if (current->ptrace & PT_TRACE_VFORK)
+                        return PTRACE_EVENT_VFORK;
+        } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
+                if (current->ptrace & PT_TRACE_CLONE)
+                        return PTRACE_EVENT_CLONE;
+        } else if (current->ptrace & PT_TRACE_FORK)
+                return PTRACE_EVENT_FORK;
+
+        return 0;
+}
+
+/*
+ *  Ok, this is the main fork-routine.
+ *
+ * It copies the process, and if successful kick-starts
+ * it and waits for it to finish using the VM if required.
+ */
+long do_fork(unsigned long clone_flags,
+              unsigned long stack_start,
+              struct pt_regs *regs,
+              unsigned long stack_size,
+              int __user *parent_tidptr,
+              int __user *child_tidptr)
+{
+        struct task_struct *p;
+        int trace = 0;
+        long pid = alloc_pidmap();
+
+        if (pid < 0)
+                return -EAGAIN;
+        if (unlikely(current->ptrace)) {
+                trace = fork_traceflag (clone_flags);
+                if (trace)
+                        clone_flags |= CLONE_PTRACE;
+        }
+
+        p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid);
+        /*
+         * Do this prior waking up the new thread - the thread pointer
+         * might get invalid after that point, if the thread exits quickly.
+         */
+        if (!IS_ERR(p)) {
+                struct completion vfork;
+
+                if (clone_flags & CLONE_VFORK) {
+                        p->vfork_done = &vfork;
+                        init_completion(&vfork);
+                }
+
+                if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) {
+                        /*
+                         * We'll start up with an immediate SIGSTOP.
+                         */
+                        sigaddset(&p->pending.signal, SIGSTOP);
+                        set_tsk_thread_flag(p, TIF_SIGPENDING);
+                }
+
+                if (!(clone_flags & CLONE_STOPPED))
+                        wake_up_new_task(p, clone_flags);
+                else
+                        p->state = TASK_STOPPED;
+
+                if (unlikely (trace)) {
+                        current->ptrace_message = pid;
+                        ptrace_notify ((trace << 8) | SIGTRAP);
+                }
+
+                if (clone_flags & CLONE_VFORK) {
+                        wait_for_completion(&vfork);
+                        if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE))
+                                ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
+                }
+        } else {
+                free_pidmap(pid);
+                pid = PTR_ERR(p);
+        }
+        return pid;
+}
+
+void __init proc_caches_init(void)
+{
+        sighand_cachep = kmem_cache_create("sighand_cache",
+                        sizeof(struct sighand_struct), 0,
+                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+        signal_cachep = kmem_cache_create("signal_cache",
+                        sizeof(struct signal_struct), 0,
+                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+        files_cachep = kmem_cache_create("files_cache", 
+                        sizeof(struct files_struct), 0,
+                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+        fs_cachep = kmem_cache_create("fs_cache", 
+                        sizeof(struct fs_struct), 0,
+                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+        vm_area_cachep = kmem_cache_create("vm_area_struct",
+                        sizeof(struct vm_area_struct), 0,
+                        SLAB_PANIC, NULL, NULL);
+        mm_cachep = kmem_cache_create("mm_struct",
+                        sizeof(struct mm_struct), 0,
+                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+}