kernel/fork.c

   1 /*
   2  *  linux/kernel/fork.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /*
   8  *  'fork.c' contains the help-routines for the 'fork' system call
   9  * (see also entry.S and others).
  10  * Fork is rather simple, once you get the hang of it, but the memory
  11  * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/slab.h>
  16 #include <linux/init.h>
  17 #include <linux/unistd.h>
  18 #include <linux/smp_lock.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/completion.h>
  22 #include <linux/namespace.h>
  23 #include <linux/personality.h>
  24 #include <linux/mempolicy.h>
  25 #include <linux/sem.h>
  26 #include <linux/file.h>
  27 #include <linux/key.h>
  28 #include <linux/binfmts.h>
  29 #include <linux/mman.h>
  30 #include <linux/fs.h>
  31 #include <linux/cpu.h>
  32 #include <linux/cpuset.h>
  33 #include <linux/security.h>
  34 #include <linux/swap.h>
  35 #include <linux/syscalls.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/futex.h>
  38 #include <linux/rcupdate.h>
  39 #include <linux/ptrace.h>
  40 #include <linux/mount.h>
  41 #include <linux/audit.h>
  42 #include <linux/profile.h>
  43 #include <linux/rmap.h>
  44 #include <linux/acct.h>
  45 #include <linux/cn_proc.h>
  46
  47 #include <asm/pgtable.h>
  48 #include <asm/pgalloc.h>
  49 #include <asm/uaccess.h>
  50 #include <asm/mmu_context.h>
  51 #include <asm/cacheflush.h>
  52 #include <asm/tlbflush.h>
  53
  54 /*
  55  * Protected counters by write_lock_irq(&tasklist_lock)
  56  */
  57 unsigned long total_forks;      /* Handle normal Linux uptimes. */
  58 int nr_threads;                 /* The idle threads do not count.. */
  59
  60 int max_threads;                /* tunable limit on nr_threads */
  61
  62 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
  63
  64  __cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */
  65
  66 EXPORT_SYMBOL(tasklist_lock);
  67
  68 int nr_processes(void)
  69 {
  70         int cpu;
  71         int total = 0;
  72
  73         for_each_online_cpu(cpu)
  74                 total += per_cpu(process_counts, cpu);
  75
  76         return total;
  77 }
  78
  79 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
  80 # define alloc_task_struct()    kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
  81 # define free_task_struct(tsk)  kmem_cache_free(task_struct_cachep, (tsk))
  82 static kmem_cache_t *task_struct_cachep;
  83 #endif
  84
  85 /* SLAB cache for signal_struct structures (tsk->signal) */
  86 kmem_cache_t *signal_cachep;
  87
  88 /* SLAB cache for sighand_struct structures (tsk->sighand) */
  89 kmem_cache_t *sighand_cachep;
  90
  91 /* SLAB cache for files_struct structures (tsk->files) */
  92 kmem_cache_t *files_cachep;
  93
  94 /* SLAB cache for fs_struct structures (tsk->fs) */
  95 kmem_cache_t *fs_cachep;
  96
  97 /* SLAB cache for vm_area_struct structures */
  98 kmem_cache_t *vm_area_cachep;
  99
 100 /* SLAB cache for mm_struct structures (tsk->mm) */
 101 static kmem_cache_t *mm_cachep;
 102
 103 void free_task(struct task_struct *tsk)
 104 {
 105         free_thread_info(tsk->thread_info);
 106         free_task_struct(tsk);
 107 }
 108 EXPORT_SYMBOL(free_task);
 109
 110 void __put_task_struct(struct task_struct *tsk)
 111 {
 112         WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)));
 113         WARN_ON(atomic_read(&tsk->usage));
 114         WARN_ON(tsk == current);
 115
 116         if (unlikely(tsk->audit_context))
 117                 audit_free(tsk);
 118         security_task_free(tsk);
 119         free_uid(tsk->user);
 120         put_group_info(tsk->group_info);
 121
 122         if (!profile_handoff_task(tsk))
 123                 free_task(tsk);
 124 }
 125
 126 void __init fork_init(unsigned long mempages)
 127 {
 128 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
 129 #ifndef ARCH_MIN_TASKALIGN
 130 #define ARCH_MIN_TASKALIGN      L1_CACHE_BYTES
 131 #endif
 132         /* create a slab on which task_structs can be allocated */
 133         task_struct_cachep =
 134                 kmem_cache_create("task_struct", sizeof(struct task_struct),
 135                         ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL);
 136 #endif
 137
 138         /*
 139          * The default maximum number of threads is set to a safe
 140          * value: the thread structures can take up at most half
 141          * of memory.
 142          */
 143         max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE);
 144
 145         /*
 146          * we need to allow at least 20 threads to boot a system
 147          */
 148         if(max_threads < 20)
 149                 max_threads = 20;
 150
 151         init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
 152         init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
 153         init_task.signal->rlim[RLIMIT_SIGPENDING] =
 154                 init_task.signal->rlim[RLIMIT_NPROC];
 155 }
 156
 157 static struct task_struct *dup_task_struct(struct task_struct *orig)
 158 {
 159         struct task_struct *tsk;
 160         struct thread_info *ti;
 161
 162         prepare_to_copy(orig);
 163
 164         tsk = alloc_task_struct();
 165         if (!tsk)
 166                 return NULL;
 167
 168         ti = alloc_thread_info(tsk);
 169         if (!ti) {
 170                 free_task_struct(tsk);
 171                 return NULL;
 172         }
 173
 174         *tsk = *orig;
 175         tsk->thread_info = ti;
 176         setup_thread_stack(tsk, orig);
 177
 178         /* One for us, one for whoever does the "release_task()" (usually parent) */
 179         atomic_set(&tsk->usage,2);
 180         atomic_set(&tsk->fs_excl, 0);
 181         return tsk;
 182 }
 183
 184 #ifdef CONFIG_MMU
 185 static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 186 {
 187         struct vm_area_struct *mpnt, *tmp, **pprev;
 188         struct rb_node **rb_link, *rb_parent;
 189         int retval;
 190         unsigned long charge;
 191         struct mempolicy *pol;
 192
 193         down_write(&oldmm->mmap_sem);
 194         flush_cache_mm(oldmm);
 195         down_write(&mm->mmap_sem);
 196
 197         mm->locked_vm = 0;
 198         mm->mmap = NULL;
 199         mm->mmap_cache = NULL;
 200         mm->free_area_cache = oldmm->mmap_base;
 201         mm->cached_hole_size = ~0UL;
 202         mm->map_count = 0;
 203         cpus_clear(mm->cpu_vm_mask);
 204         mm->mm_rb = RB_ROOT;
 205         rb_link = &mm->mm_rb.rb_node;
 206         rb_parent = NULL;
 207         pprev = &mm->mmap;
 208
 209         for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
 210                 struct file *file;
 211
 212                 if (mpnt->vm_flags & VM_DONTCOPY) {
 213                         long pages = vma_pages(mpnt);
 214                         mm->total_vm -= pages;
 215                         vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file,
 216                                                                 -pages);
 217                         continue;
 218                 }
 219                 charge = 0;
 220                 if (mpnt->vm_flags & VM_ACCOUNT) {
 221                         unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
 222                         if (security_vm_enough_memory(len))
 223                                 goto fail_nomem;
 224                         charge = len;
 225                 }
 226                 tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 227                 if (!tmp)
 228                         goto fail_nomem;
 229                 *tmp = *mpnt;
 230                 pol = mpol_copy(vma_policy(mpnt));
 231                 retval = PTR_ERR(pol);
 232                 if (IS_ERR(pol))
 233                         goto fail_nomem_policy;
 234                 vma_set_policy(tmp, pol);
 235                 tmp->vm_flags &= ~VM_LOCKED;
 236                 tmp->vm_mm = mm;
 237                 tmp->vm_next = NULL;
 238                 anon_vma_link(tmp);
 239                 file = tmp->vm_file;
 240                 if (file) {
 241                         struct inode *inode = file->f_dentry->d_inode;
 242                         get_file(file);
 243                         if (tmp->vm_flags & VM_DENYWRITE)
 244                                 atomic_dec(&inode->i_writecount);
 245
 246                         /* insert tmp into the share list, just after mpnt */
 247                         spin_lock(&file->f_mapping->i_mmap_lock);
 248                         tmp->vm_truncate_count = mpnt->vm_truncate_count;
 249                         flush_dcache_mmap_lock(file->f_mapping);
 250                         vma_prio_tree_add(tmp, mpnt);
 251                         flush_dcache_mmap_unlock(file->f_mapping);
 252                         spin_unlock(&file->f_mapping->i_mmap_lock);
 253                 }
 254
 255                 /*
 256                  * Link in the new vma and copy the page table entries.
 257                  */
 258                 *pprev = tmp;
 259                 pprev = &tmp->vm_next;
 260
 261                 __vma_link_rb(mm, tmp, rb_link, rb_parent);
 262                 rb_link = &tmp->vm_rb.rb_right;
 263                 rb_parent = &tmp->vm_rb;
 264
 265                 mm->map_count++;
 266                 retval = copy_page_range(mm, oldmm, mpnt);
 267
 268                 if (tmp->vm_ops && tmp->vm_ops->open)
 269                         tmp->vm_ops->open(tmp);
 270
 271                 if (retval)
 272                         goto out;
 273         }
 274         retval = 0;
 275 out:
 276         up_write(&mm->mmap_sem);
 277         flush_tlb_mm(oldmm);
 278         up_write(&oldmm->mmap_sem);
 279         return retval;
 280 fail_nomem_policy:
 281         kmem_cache_free(vm_area_cachep, tmp);
 282 fail_nomem:
 283         retval = -ENOMEM;
 284         vm_unacct_memory(charge);
 285         goto out;
 286 }
 287
 288 static inline int mm_alloc_pgd(struct mm_struct * mm)
 289 {
 290         mm->pgd = pgd_alloc(mm);
 291         if (unlikely(!mm->pgd))
 292                 return -ENOMEM;
 293         return 0;
 294 }
 295
 296 static inline void mm_free_pgd(struct mm_struct * mm)
 297 {
 298         pgd_free(mm->pgd);
 299 }
 300 #else
 301 #define dup_mmap(mm, oldmm)     (0)
 302 #define mm_alloc_pgd(mm)        (0)
 303 #define mm_free_pgd(mm)
 304 #endif /* CONFIG_MMU */
 305
 306  __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
 307
 308 #define allocate_mm()   (kmem_cache_alloc(mm_cachep, SLAB_KERNEL))
 309 #define free_mm(mm)     (kmem_cache_free(mm_cachep, (mm)))
 310
 311 #include <linux/init_task.h>
 312
 313 static struct mm_struct * mm_init(struct mm_struct * mm)
 314 {
 315         atomic_set(&mm->mm_users, 1);
 316         atomic_set(&mm->mm_count, 1);
 317         init_rwsem(&mm->mmap_sem);
 318         INIT_LIST_HEAD(&mm->mmlist);
 319         mm->core_waiters = 0;
 320         mm->nr_ptes = 0;
 321         set_mm_counter(mm, file_rss, 0);
 322         set_mm_counter(mm, anon_rss, 0);
 323         spin_lock_init(&mm->page_table_lock);
 324         rwlock_init(&mm->ioctx_list_lock);
 325         mm->ioctx_list = NULL;
 326         mm->free_area_cache = TASK_UNMAPPED_BASE;
 327         mm->cached_hole_size = ~0UL;
 328
 329         if (likely(!mm_alloc_pgd(mm))) {
 330                 mm->def_flags = 0;
 331                 return mm;
 332         }
 333         free_mm(mm);
 334         return NULL;
 335 }
 336
 337 /*
 338  * Allocate and initialize an mm_struct.
 339  */
 340 struct mm_struct * mm_alloc(void)
 341 {
 342         struct mm_struct * mm;
 343
 344         mm = allocate_mm();
 345         if (mm) {
 346                 memset(mm, 0, sizeof(*mm));
 347                 mm = mm_init(mm);
 348         }
 349         return mm;
 350 }
 351
 352 /*
 353  * Called when the last reference to the mm
 354  * is dropped: either by a lazy thread or by
 355  * mmput. Free the page directory and the mm.
 356  */
 357 void fastcall __mmdrop(struct mm_struct *mm)
 358 {
 359         BUG_ON(mm == &init_mm);
 360         mm_free_pgd(mm);
 361         destroy_context(mm);
 362         free_mm(mm);
 363 }
 364
 365 /*
 366  * Decrement the use count and release all resources for an mm.
 367  */
 368 void mmput(struct mm_struct *mm)
 369 {
 370         if (atomic_dec_and_test(&mm->mm_users)) {
 371                 exit_aio(mm);
 372                 exit_mmap(mm);
 373                 if (!list_empty(&mm->mmlist)) {
 374                         spin_lock(&mmlist_lock);
 375                         list_del(&mm->mmlist);
 376                         spin_unlock(&mmlist_lock);
 377                 }
 378                 put_swap_token(mm);
 379                 mmdrop(mm);
 380         }
 381 }
 382 EXPORT_SYMBOL_GPL(mmput);
 383
 384 /**
 385  * get_task_mm - acquire a reference to the task's mm
 386  *
 387  * Returns %NULL if the task has no mm.  Checks PF_BORROWED_MM (meaning
 388  * this kernel workthread has transiently adopted a user mm with use_mm,
 389  * to do its AIO) is not set and if so returns a reference to it, after
 390  * bumping up the use count.  User must release the mm via mmput()
 391  * after use.  Typically used by /proc and ptrace.
 392  */
 393 struct mm_struct *get_task_mm(struct task_struct *task)
 394 {
 395         struct mm_struct *mm;
 396
 397         task_lock(task);
 398         mm = task->mm;
 399         if (mm) {
 400                 if (task->flags & PF_BORROWED_MM)
 401                         mm = NULL;
 402                 else
 403                         atomic_inc(&mm->mm_users);
 404         }
 405         task_unlock(task);
 406         return mm;
 407 }
 408 EXPORT_SYMBOL_GPL(get_task_mm);
 409
 410 /* Please note the differences between mmput and mm_release.
 411  * mmput is called whenever we stop holding onto a mm_struct,
 412  * error success whatever.
 413  *
 414  * mm_release is called after a mm_struct has been removed
 415  * from the current process.
 416  *
 417  * This difference is important for error handling, when we
 418  * only half set up a mm_struct for a new process and need to restore
 419  * the old one.  Because we mmput the new mm_struct before
 420  * restoring the old one. . .
 421  * Eric Biederman 10 January 1998
 422  */
 423 void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 424 {
 425         struct completion *vfork_done = tsk->vfork_done;
 426
 427         /* Get rid of any cached register state */
 428         deactivate_mm(tsk, mm);
 429
 430         /* notify parent sleeping on vfork() */
 431         if (vfork_done) {
 432                 tsk->vfork_done = NULL;
 433                 complete(vfork_done);
 434         }
 435         if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) {
 436                 u32 __user * tidptr = tsk->clear_child_tid;
 437                 tsk->clear_child_tid = NULL;
 438
 439                 /*
 440                  * We don't check the error code - if userspace has
 441                  * not set up a proper pointer then tough luck.
 442                  */
 443                 put_user(0, tidptr);
 444                 sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0);
 445         }
 446 }
 447
 448 static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
 449 {
 450         struct mm_struct * mm, *oldmm;
 451         int retval;
 452
 453         tsk->min_flt = tsk->maj_flt = 0;
 454         tsk->nvcsw = tsk->nivcsw = 0;
 455
 456         tsk->mm = NULL;
 457         tsk->active_mm = NULL;
 458
 459         /*
 460          * Are we cloning a kernel thread?
 461          *
 462          * We need to steal a active VM for that..
 463          */
 464         oldmm = current->mm;
 465         if (!oldmm)
 466                 return 0;
 467
 468         if (clone_flags & CLONE_VM) {
 469                 atomic_inc(&oldmm->mm_users);
 470                 mm = oldmm;
 471                 goto good_mm;
 472         }
 473
 474         retval = -ENOMEM;
 475         mm = allocate_mm();
 476         if (!mm)
 477                 goto fail_nomem;
 478
 479         /* Copy the current MM stuff.. */
 480         memcpy(mm, oldmm, sizeof(*mm));
 481         if (!mm_init(mm))
 482                 goto fail_nomem;
 483
 484         if (init_new_context(tsk,mm))
 485                 goto fail_nocontext;
 486
 487         retval = dup_mmap(mm, oldmm);
 488         if (retval)
 489                 goto free_pt;
 490
 491         mm->hiwater_rss = get_mm_rss(mm);
 492         mm->hiwater_vm = mm->total_vm;
 493
 494 good_mm:
 495         tsk->mm = mm;
 496         tsk->active_mm = mm;
 497         return 0;
 498
 499 free_pt:
 500         mmput(mm);
 501 fail_nomem:
 502         return retval;
 503
 504 fail_nocontext:
 505         /*
 506          * If init_new_context() failed, we cannot use mmput() to free the mm
 507          * because it calls destroy_context()
 508          */
 509         mm_free_pgd(mm);
 510         free_mm(mm);
 511         return retval;
 512 }
 513
 514 static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
 515 {
 516         struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
 517         /* We don't need to lock fs - think why ;-) */
 518         if (fs) {
 519                 atomic_set(&fs->count, 1);
 520                 rwlock_init(&fs->lock);
 521                 fs->umask = old->umask;
 522                 read_lock(&old->lock);
 523                 fs->rootmnt = mntget(old->rootmnt);
 524                 fs->root = dget(old->root);
 525                 fs->pwdmnt = mntget(old->pwdmnt);
 526                 fs->pwd = dget(old->pwd);
 527                 if (old->altroot) {
 528                         fs->altrootmnt = mntget(old->altrootmnt);
 529                         fs->altroot = dget(old->altroot);
 530                 } else {
 531                         fs->altrootmnt = NULL;
 532                         fs->altroot = NULL;
 533                 }
 534                 read_unlock(&old->lock);
 535         }
 536         return fs;
 537 }
 538
 539 struct fs_struct *copy_fs_struct(struct fs_struct *old)
 540 {
 541         return __copy_fs_struct(old);
 542 }
 543
 544 EXPORT_SYMBOL_GPL(copy_fs_struct);
 545
 546 static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
 547 {
 548         if (clone_flags & CLONE_FS) {
 549                 atomic_inc(&current->fs->count);
 550                 return 0;
 551         }
 552         tsk->fs = __copy_fs_struct(current->fs);
 553         if (!tsk->fs)
 554                 return -ENOMEM;
 555         return 0;
 556 }
 557
 558 static int count_open_files(struct fdtable *fdt)
 559 {
 560         int size = fdt->max_fdset;
 561         int i;
 562
 563         /* Find the last open fd */
 564         for (i = size/(8*sizeof(long)); i > 0; ) {
 565                 if (fdt->open_fds->fds_bits[--i])
 566                         break;
 567         }
 568         i = (i+1) * 8 * sizeof(long);
 569         return i;
 570 }
 571
 572 static struct files_struct *alloc_files(void)
 573 {
 574         struct files_struct *newf;
 575         struct fdtable *fdt;
 576
 577         newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL);
 578         if (!newf)
 579                 goto out;
 580
 581         atomic_set(&newf->count, 1);
 582
 583         spin_lock_init(&newf->file_lock);
 584         fdt = &newf->fdtab;
 585         fdt->next_fd = 0;
 586         fdt->max_fds = NR_OPEN_DEFAULT;
 587         fdt->max_fdset = __FD_SETSIZE;
 588         fdt->close_on_exec = &newf->close_on_exec_init;
 589         fdt->open_fds = &newf->open_fds_init;
 590         fdt->fd = &newf->fd_array[0];
 591         INIT_RCU_HEAD(&fdt->rcu);
 592         fdt->free_files = NULL;
 593         fdt->next = NULL;
 594         rcu_assign_pointer(newf->fdt, fdt);
 595 out:
 596         return newf;
 597 }
 598
 599 static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
 600 {
 601         struct files_struct *oldf, *newf;
 602         struct file **old_fds, **new_fds;
 603         int open_files, size, i, error = 0, expand;
 604         struct fdtable *old_fdt, *new_fdt;
 605
 606         /*
 607          * A background process may not have any files ...
 608          */
 609         oldf = current->files;
 610         if (!oldf)
 611                 goto out;
 612
 613         if (clone_flags & CLONE_FILES) {
 614                 atomic_inc(&oldf->count);
 615                 goto out;
 616         }
 617
 618         /*
 619          * Note: we may be using current for both targets (See exec.c)
 620          * This works because we cache current->files (old) as oldf. Don't
 621          * break this.
 622          */
 623         tsk->files = NULL;
 624         error = -ENOMEM;
 625         newf = alloc_files();
 626         if (!newf)
 627                 goto out;
 628
 629         spin_lock(&oldf->file_lock);
 630         old_fdt = files_fdtable(oldf);
 631         new_fdt = files_fdtable(newf);
 632         size = old_fdt->max_fdset;
 633         open_files = count_open_files(old_fdt);
 634         expand = 0;
 635
 636         /*
 637          * Check whether we need to allocate a larger fd array or fd set.
 638          * Note: we're not a clone task, so the open count won't  change.
 639          */
 640         if (open_files > new_fdt->max_fdset) {
 641                 new_fdt->max_fdset = 0;
 642                 expand = 1;
 643         }
 644         if (open_files > new_fdt->max_fds) {
 645                 new_fdt->max_fds = 0;
 646                 expand = 1;
 647         }
 648
 649         /* if the old fdset gets grown now, we'll only copy up to "size" fds */
 650         if (expand) {
 651                 spin_unlock(&oldf->file_lock);
 652                 spin_lock(&newf->file_lock);
 653                 error = expand_files(newf, open_files-1);
 654                 spin_unlock(&newf->file_lock);
 655                 if (error < 0)
 656                         goto out_release;
 657                 new_fdt = files_fdtable(newf);
 658                 /*
 659                  * Reacquire the oldf lock and a pointer to its fd table
 660                  * who knows it may have a new bigger fd table. We need
 661                  * the latest pointer.
 662                  */
 663                 spin_lock(&oldf->file_lock);
 664                 old_fdt = files_fdtable(oldf);
 665         }
 666
 667         old_fds = old_fdt->fd;
 668         new_fds = new_fdt->fd;
 669
 670         memcpy(new_fdt->open_fds->fds_bits, old_fdt->open_fds->fds_bits, open_files/8);
 671         memcpy(new_fdt->close_on_exec->fds_bits, old_fdt->close_on_exec->fds_bits, open_files/8);
 672
 673         for (i = open_files; i != 0; i--) {
 674                 struct file *f = *old_fds++;
 675                 if (f) {
 676                         get_file(f);
 677                 } else {
 678                         /*
 679                          * The fd may be claimed in the fd bitmap but not yet
 680                          * instantiated in the files array if a sibling thread
 681                          * is partway through open().  So make sure that this
 682                          * fd is available to the new process.
 683                          */
 684                         FD_CLR(open_files - i, new_fdt->open_fds);
 685                 }
 686                 rcu_assign_pointer(*new_fds++, f);
 687         }
 688         spin_unlock(&oldf->file_lock);
 689
 690         /* compute the remainder to be cleared */
 691         size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
 692
 693         /* This is long word aligned thus could use a optimized version */
 694         memset(new_fds, 0, size);
 695
 696         if (new_fdt->max_fdset > open_files) {
 697                 int left = (new_fdt->max_fdset-open_files)/8;
 698                 int start = open_files / (8 * sizeof(unsigned long));
 699
 700                 memset(&new_fdt->open_fds->fds_bits[start], 0, left);
 701                 memset(&new_fdt->close_on_exec->fds_bits[start], 0, left);
 702         }
 703
 704         tsk->files = newf;
 705         error = 0;
 706 out:
 707         return error;
 708
 709 out_release:
 710         free_fdset (new_fdt->close_on_exec, new_fdt->max_fdset);
 711         free_fdset (new_fdt->open_fds, new_fdt->max_fdset);
 712         free_fd_array(new_fdt->fd, new_fdt->max_fds);
 713         kmem_cache_free(files_cachep, newf);
 714         goto out;
 715 }
 716
 717 /*
 718  *      Helper to unshare the files of the current task.
 719  *      We don't want to expose copy_files internals to
 720  *      the exec layer of the kernel.
 721  */
 722
 723 int unshare_files(void)
 724 {
 725         struct files_struct *files  = current->files;
 726         int rc;
 727
 728         if(!files)
 729                 BUG();
 730
 731         /* This can race but the race causes us to copy when we don't
 732            need to and drop the copy */
 733         if(atomic_read(&files->count) == 1)
 734         {
 735                 atomic_inc(&files->count);
 736                 return 0;
 737         }
 738         rc = copy_files(0, current);
 739         if(rc)
 740                 current->files = files;
 741         return rc;
 742 }
 743
 744 EXPORT_SYMBOL(unshare_files);
 745
 746 void sighand_free_cb(struct rcu_head *rhp)
 747 {
 748         struct sighand_struct *sp;
 749
 750         sp = container_of(rhp, struct sighand_struct, rcu);
 751         kmem_cache_free(sighand_cachep, sp);
 752 }
 753
 754 static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
 755 {
 756         struct sighand_struct *sig;
 757
 758         if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) {
 759                 atomic_inc(&current->sighand->count);
 760                 return 0;
 761         }
 762         sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
 763         rcu_assign_pointer(tsk->sighand, sig);
 764         if (!sig)
 765                 return -ENOMEM;
 766         spin_lock_init(&sig->siglock);
 767         atomic_set(&sig->count, 1);
 768         memcpy(sig->action, current->sighand->action, sizeof(sig->action));
 769         return 0;
 770 }
 771
 772 static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk)
 773 {
 774         struct signal_struct *sig;
 775         int ret;
 776
 777         if (clone_flags & CLONE_THREAD) {
 778                 atomic_inc(&current->signal->count);
 779                 atomic_inc(&current->signal->live);
 780                 return 0;
 781         }
 782         sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
 783         tsk->signal = sig;
 784         if (!sig)
 785                 return -ENOMEM;
 786
 787         ret = copy_thread_group_keys(tsk);
 788         if (ret < 0) {
 789                 kmem_cache_free(signal_cachep, sig);
 790                 return ret;
 791         }
 792
 793         atomic_set(&sig->count, 1);
 794         atomic_set(&sig->live, 1);
 795         init_waitqueue_head(&sig->wait_chldexit);
 796         sig->flags = 0;
 797         sig->group_exit_code = 0;
 798         sig->group_exit_task = NULL;
 799         sig->group_stop_count = 0;
 800         sig->curr_target = NULL;
 801         init_sigpending(&sig->shared_pending);
 802         INIT_LIST_HEAD(&sig->posix_timers);
 803
 804         hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC);
 805         sig->it_real_incr.tv64 = 0;
 806         sig->real_timer.function = it_real_fn;
 807         sig->real_timer.data = tsk;
 808
 809         sig->it_virt_expires = cputime_zero;
 810         sig->it_virt_incr = cputime_zero;
 811         sig->it_prof_expires = cputime_zero;
 812         sig->it_prof_incr = cputime_zero;
 813
 814         sig->leader = 0;        /* session leadership doesn't inherit */
 815         sig->tty_old_pgrp = 0;
 816
 817         sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero;
 818         sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0;
 819         sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0;
 820         sig->sched_time = 0;
 821         INIT_LIST_HEAD(&sig->cpu_timers[0]);
 822         INIT_LIST_HEAD(&sig->cpu_timers[1]);
 823         INIT_LIST_HEAD(&sig->cpu_timers[2]);
 824
 825         task_lock(current->group_leader);
 826         memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
 827         task_unlock(current->group_leader);
 828
 829         if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
 830                 /*
 831                  * New sole thread in the process gets an expiry time
 832                  * of the whole CPU time limit.
 833                  */
 834                 tsk->it_prof_expires =
 835                         secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
 836         }
 837
 838         return 0;
 839 }
 840
 841 static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
 842 {
 843         unsigned long new_flags = p->flags;
 844
 845         new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE);
 846         new_flags |= PF_FORKNOEXEC;
 847         if (!(clone_flags & CLONE_PTRACE))
 848                 p->ptrace = 0;
 849         p->flags = new_flags;
 850 }
 851
 852 asmlinkage long sys_set_tid_address(int __user *tidptr)
 853 {
 854         current->clear_child_tid = tidptr;
 855
 856         return current->pid;
 857 }
 858
 859 /*
 860  * This creates a new process as a copy of the old one,
 861  * but does not actually start it yet.
 862  *
 863  * It copies the registers, and all the appropriate
 864  * parts of the process environment (as per the clone
 865  * flags). The actual kick-off is left to the caller.
 866  */
 867 static task_t *copy_process(unsigned long clone_flags,
 868                                  unsigned long stack_start,
 869                                  struct pt_regs *regs,
 870                                  unsigned long stack_size,
 871                                  int __user *parent_tidptr,
 872                                  int __user *child_tidptr,
 873                                  int pid)
 874 {
 875         int retval;
 876         struct task_struct *p = NULL;
 877
 878         if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
 879                 return ERR_PTR(-EINVAL);
 880
 881         /*
 882          * Thread groups must share signals as well, and detached threads
 883          * can only be started up within the thread group.
 884          */
 885         if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
 886                 return ERR_PTR(-EINVAL);
 887
 888         /*
 889          * Shared signal handlers imply shared VM. By way of the above,
 890          * thread groups also imply shared VM. Blocking this case allows
 891          * for various simplifications in other code.
 892          */
 893         if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
 894                 return ERR_PTR(-EINVAL);
 895
 896         retval = security_task_create(clone_flags);
 897         if (retval)
 898                 goto fork_out;
 899
 900         retval = -ENOMEM;
 901         p = dup_task_struct(current);
 902         if (!p)
 903                 goto fork_out;
 904
 905         retval = -EAGAIN;
 906         if (atomic_read(&p->user->processes) >=
 907                         p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
 908                 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
 909                                 p->user != &root_user)
 910                         goto bad_fork_free;
 911         }
 912
 913         atomic_inc(&p->user->__count);
 914         atomic_inc(&p->user->processes);
 915         get_group_info(p->group_info);
 916
 917         /*
 918          * If multiple threads are within copy_process(), then this check
 919          * triggers too late. This doesn't hurt, the check is only there
 920          * to stop root fork bombs.
 921          */
 922         if (nr_threads >= max_threads)
 923                 goto bad_fork_cleanup_count;
 924
 925         if (!try_module_get(task_thread_info(p)->exec_domain->module))
 926                 goto bad_fork_cleanup_count;
 927
 928         if (p->binfmt && !try_module_get(p->binfmt->module))
 929                 goto bad_fork_cleanup_put_domain;
 930
 931         p->did_exec = 0;
 932         copy_flags(clone_flags, p);
 933         p->pid = pid;
 934         retval = -EFAULT;
 935         if (clone_flags & CLONE_PARENT_SETTID)
 936                 if (put_user(p->pid, parent_tidptr))
 937                         goto bad_fork_cleanup;
 938
 939         p->proc_dentry = NULL;
 940
 941         INIT_LIST_HEAD(&p->children);
 942         INIT_LIST_HEAD(&p->sibling);
 943         p->vfork_done = NULL;
 944         spin_lock_init(&p->alloc_lock);
 945         spin_lock_init(&p->proc_lock);
 946
 947         clear_tsk_thread_flag(p, TIF_SIGPENDING);
 948         init_sigpending(&p->pending);
 949
 950         p->utime = cputime_zero;
 951         p->stime = cputime_zero;
 952         p->sched_time = 0;
 953         p->rchar = 0;           /* I/O counter: bytes read */
 954         p->wchar = 0;           /* I/O counter: bytes written */
 955         p->syscr = 0;           /* I/O counter: read syscalls */
 956         p->syscw = 0;           /* I/O counter: write syscalls */
 957         acct_clear_integrals(p);
 958
 959         p->it_virt_expires = cputime_zero;
 960         p->it_prof_expires = cputime_zero;
 961         p->it_sched_expires = 0;
 962         INIT_LIST_HEAD(&p->cpu_timers[0]);
 963         INIT_LIST_HEAD(&p->cpu_timers[1]);
 964         INIT_LIST_HEAD(&p->cpu_timers[2]);
 965
 966         p->lock_depth = -1;             /* -1 = no lock */
 967         do_posix_clock_monotonic_gettime(&p->start_time);
 968         p->security = NULL;
 969         p->io_context = NULL;
 970         p->io_wait = NULL;
 971         p->audit_context = NULL;
 972         cpuset_fork(p);
 973 #ifdef CONFIG_NUMA
 974         p->mempolicy = mpol_copy(p->mempolicy);
 975         if (IS_ERR(p->mempolicy)) {
 976                 retval = PTR_ERR(p->mempolicy);
 977                 p->mempolicy = NULL;
 978                 goto bad_fork_cleanup_cpuset;
 979         }
 980 #endif
 981
 982 #ifdef CONFIG_DEBUG_MUTEXES
 983         p->blocked_on = NULL; /* not blocked yet */
 984 #endif
 985
 986         p->tgid = p->pid;
 987         if (clone_flags & CLONE_THREAD)
 988                 p->tgid = current->tgid;
 989
 990         if ((retval = security_task_alloc(p)))
 991                 goto bad_fork_cleanup_policy;
 992         if ((retval = audit_alloc(p)))
 993                 goto bad_fork_cleanup_security;
 994         /* copy all the process information */
 995         if ((retval = copy_semundo(clone_flags, p)))
 996                 goto bad_fork_cleanup_audit;
 997         if ((retval = copy_files(clone_flags, p)))
 998                 goto bad_fork_cleanup_semundo;
 999         if ((retval = copy_fs(clone_flags, p)))
1000                 goto bad_fork_cleanup_files;
1001         if ((retval = copy_sighand(clone_flags, p)))
1002                 goto bad_fork_cleanup_fs;
1003         if ((retval = copy_signal(clone_flags, p)))
1004                 goto bad_fork_cleanup_sighand;
1005         if ((retval = copy_mm(clone_flags, p)))
1006                 goto bad_fork_cleanup_signal;
1007         if ((retval = copy_keys(clone_flags, p)))
1008                 goto bad_fork_cleanup_mm;
1009         if ((retval = copy_namespace(clone_flags, p)))
1010                 goto bad_fork_cleanup_keys;
1011         retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
1012         if (retval)
1013                 goto bad_fork_cleanup_namespace;
1014
1015         p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
1016         /*
1017          * Clear TID on mm_release()?
1018          */
1019         p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
1020
1021         /*
1022          * Syscall tracing should be turned off in the child regardless
1023          * of CLONE_PTRACE.
1024          */
1025         clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
1026 #ifdef TIF_SYSCALL_EMU
1027         clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
1028 #endif
1029
1030         /* Our parent execution domain becomes current domain
1031            These must match for thread signalling to apply */
1032
1033         p->parent_exec_id = p->self_exec_id;
1034
1035         /* ok, now we should be set up.. */
1036         p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
1037         p->pdeath_signal = 0;
1038         p->exit_state = 0;
1039
1040         /*
1041          * Ok, make it visible to the rest of the system.
1042          * We dont wake it up yet.
1043          */
1044         p->group_leader = p;
1045         INIT_LIST_HEAD(&p->ptrace_children);
1046         INIT_LIST_HEAD(&p->ptrace_list);
1047
1048         /* Perform scheduler related setup. Assign this task to a CPU. */
1049         sched_fork(p, clone_flags);
1050
1051         /* Need tasklist lock for parent etc handling! */
1052         write_lock_irq(&tasklist_lock);
1053
1054         /*
1055          * The task hasn't been attached yet, so its cpus_allowed mask will
1056          * not be changed, nor will its assigned CPU.
1057          *
1058          * The cpus_allowed mask of the parent may have changed after it was
1059          * copied first time - so re-copy it here, then check the child's CPU
1060          * to ensure it is on a valid CPU (and if not, just force it back to
1061          * parent's CPU). This avoids alot of nasty races.
1062          */
1063         p->cpus_allowed = current->cpus_allowed;
1064         if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
1065                         !cpu_online(task_cpu(p))))
1066                 set_task_cpu(p, smp_processor_id());
1067
1068         /*
1069          * Check for pending SIGKILL! The new thread should not be allowed
1070          * to slip out of an OOM kill. (or normal SIGKILL.)
1071          */
1072         if (sigismember(&current->pending.signal, SIGKILL)) {
1073                 write_unlock_irq(&tasklist_lock);
1074                 retval = -EINTR;
1075                 goto bad_fork_cleanup_namespace;
1076         }
1077
1078         /* CLONE_PARENT re-uses the old parent */
1079         if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
1080                 p->real_parent = current->real_parent;
1081         else
1082                 p->real_parent = current;
1083         p->parent = p->real_parent;
1084
1085         if (clone_flags & CLONE_THREAD) {
1086                 spin_lock(&current->sighand->siglock);
1087                 /*
1088                  * Important: if an exit-all has been started then
1089                  * do not create this new thread - the whole thread
1090                  * group is supposed to exit anyway.
1091                  */
1092                 if (current->signal->flags & SIGNAL_GROUP_EXIT) {
1093                         spin_unlock(&current->sighand->siglock);
1094                         write_unlock_irq(&tasklist_lock);
1095                         retval = -EAGAIN;
1096                         goto bad_fork_cleanup_namespace;
1097                 }
1098                 p->group_leader = current->group_leader;
1099
1100                 if (current->signal->group_stop_count > 0) {
1101                         /*
1102                          * There is an all-stop in progress for the group.
1103                          * We ourselves will stop as soon as we check signals.
1104                          * Make the new thread part of that group stop too.
1105                          */
1106                         current->signal->group_stop_count++;
1107                         set_tsk_thread_flag(p, TIF_SIGPENDING);
1108                 }
1109
1110                 if (!cputime_eq(current->signal->it_virt_expires,
1111                                 cputime_zero) ||
1112                     !cputime_eq(current->signal->it_prof_expires,
1113                                 cputime_zero) ||
1114                     current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY ||
1115                     !list_empty(&current->signal->cpu_timers[0]) ||
1116                     !list_empty(&current->signal->cpu_timers[1]) ||
1117                     !list_empty(&current->signal->cpu_timers[2])) {
1118                         /*
1119                          * Have child wake up on its first tick to check
1120                          * for process CPU timers.
1121                          */
1122                         p->it_prof_expires = jiffies_to_cputime(1);
1123                 }
1124
1125                 spin_unlock(&current->sighand->siglock);
1126         }
1127
1128         /*
1129          * inherit ioprio
1130          */
1131         p->ioprio = current->ioprio;
1132
1133         SET_LINKS(p);
1134         if (unlikely(p->ptrace & PT_PTRACED))
1135                 __ptrace_link(p, current->parent);
1136
1137         attach_pid(p, PIDTYPE_PID, p->pid);
1138         attach_pid(p, PIDTYPE_TGID, p->tgid);
1139         if (thread_group_leader(p)) {
1140                 p->signal->tty = current->signal->tty;
1141                 p->signal->pgrp = process_group(current);
1142                 p->signal->session = current->signal->session;
1143                 attach_pid(p, PIDTYPE_PGID, process_group(p));
1144                 attach_pid(p, PIDTYPE_SID, p->signal->session);
1145                 if (p->pid)
1146                         __get_cpu_var(process_counts)++;
1147         }
1148
1149         nr_threads++;
1150         total_forks++;
1151         write_unlock_irq(&tasklist_lock);
1152         proc_fork_connector(p);
1153         return p;
1154
1155 bad_fork_cleanup_namespace:
1156         exit_namespace(p);
1157 bad_fork_cleanup_keys:
1158         exit_keys(p);
1159 bad_fork_cleanup_mm:
1160         if (p->mm)
1161                 mmput(p->mm);
1162 bad_fork_cleanup_signal:
1163         exit_signal(p);
1164 bad_fork_cleanup_sighand:
1165         exit_sighand(p);
1166 bad_fork_cleanup_fs:
1167         exit_fs(p); /* blocking */
1168 bad_fork_cleanup_files:
1169         exit_files(p); /* blocking */
1170 bad_fork_cleanup_semundo:
1171         exit_sem(p);
1172 bad_fork_cleanup_audit:
1173         audit_free(p);
1174 bad_fork_cleanup_security:
1175         security_task_free(p);
1176 bad_fork_cleanup_policy:
1177 #ifdef CONFIG_NUMA
1178         mpol_free(p->mempolicy);
1179 bad_fork_cleanup_cpuset:
1180 #endif
1181         cpuset_exit(p);
1182 bad_fork_cleanup:
1183         if (p->binfmt)
1184                 module_put(p->binfmt->module);
1185 bad_fork_cleanup_put_domain:
1186         module_put(task_thread_info(p)->exec_domain->module);
1187 bad_fork_cleanup_count:
1188         put_group_info(p->group_info);
1189         atomic_dec(&p->user->processes);
1190         free_uid(p->user);
1191 bad_fork_free:
1192         free_task(p);
1193 fork_out:
1194         return ERR_PTR(retval);
1195 }
1196
1197 struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
1198 {
1199         memset(regs, 0, sizeof(struct pt_regs));
1200         return regs;
1201 }
1202
1203 task_t * __devinit fork_idle(int cpu)
1204 {
1205         task_t *task;
1206         struct pt_regs regs;
1207
1208         task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL, NULL, 0);
1209         if (!task)
1210                 return ERR_PTR(-ENOMEM);
1211         init_idle(task, cpu);
1212         unhash_process(task);
1213         return task;
1214 }
1215
1216 static inline int fork_traceflag (unsigned clone_flags)
1217 {
1218         if (clone_flags & CLONE_UNTRACED)
1219                 return 0;
1220         else if (clone_flags & CLONE_VFORK) {
1221                 if (current->ptrace & PT_TRACE_VFORK)
1222                         return PTRACE_EVENT_VFORK;
1223         } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
1224                 if (current->ptrace & PT_TRACE_CLONE)
1225                         return PTRACE_EVENT_CLONE;
1226         } else if (current->ptrace & PT_TRACE_FORK)
1227                 return PTRACE_EVENT_FORK;
1228
1229         return 0;
1230 }
1231
1232 /*
1233  *  Ok, this is the main fork-routine.
1234  *
1235  * It copies the process, and if successful kick-starts
1236  * it and waits for it to finish using the VM if required.
1237  */
1238 long do_fork(unsigned long clone_flags,
1239               unsigned long stack_start,
1240               struct pt_regs *regs,
1241               unsigned long stack_size,
1242               int __user *parent_tidptr,
1243               int __user *child_tidptr)
1244 {
1245         struct task_struct *p;
1246         int trace = 0;
1247         long pid = alloc_pidmap();
1248
1249         if (pid < 0)
1250                 return -EAGAIN;
1251         if (unlikely(current->ptrace)) {
1252                 trace = fork_traceflag (clone_flags);
1253                 if (trace)
1254                         clone_flags |= CLONE_PTRACE;
1255         }
1256
1257         p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid);
1258         /*
1259          * Do this prior waking up the new thread - the thread pointer
1260          * might get invalid after that point, if the thread exits quickly.
1261          */
1262         if (!IS_ERR(p)) {
1263                 struct completion vfork;
1264
1265                 if (clone_flags & CLONE_VFORK) {
1266                         p->vfork_done = &vfork;
1267                         init_completion(&vfork);
1268                 }
1269
1270                 if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) {
1271                         /*
1272                          * We'll start up with an immediate SIGSTOP.
1273                          */
1274                         sigaddset(&p->pending.signal, SIGSTOP);
1275                         set_tsk_thread_flag(p, TIF_SIGPENDING);
1276                 }
1277
1278                 if (!(clone_flags & CLONE_STOPPED))
1279                         wake_up_new_task(p, clone_flags);
1280                 else
1281                         p->state = TASK_STOPPED;
1282
1283                 if (unlikely (trace)) {
1284                         current->ptrace_message = pid;
1285                         ptrace_notify ((trace << 8) | SIGTRAP);
1286                 }
1287
1288                 if (clone_flags & CLONE_VFORK) {
1289                         wait_for_completion(&vfork);
1290                         if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE))
1291                                 ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
1292                 }
1293         } else {
1294                 free_pidmap(pid);
1295                 pid = PTR_ERR(p);
1296         }
1297         return pid;
1298 }
1299
1300 void __init proc_caches_init(void)
1301 {
1302         sighand_cachep = kmem_cache_create("sighand_cache",
1303                         sizeof(struct sighand_struct), 0,
1304                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1305         signal_cachep = kmem_cache_create("signal_cache",
1306                         sizeof(struct signal_struct), 0,
1307                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1308         files_cachep = kmem_cache_create("files_cache",
1309                         sizeof(struct files_struct), 0,
1310                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1311         fs_cachep = kmem_cache_create("fs_cache",
1312                         sizeof(struct fs_struct), 0,
1313                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1314         vm_area_cachep = kmem_cache_create("vm_area_struct",
1315                         sizeof(struct vm_area_struct), 0,
1316                         SLAB_PANIC, NULL, NULL);
1317         mm_cachep = kmem_cache_create("mm_struct",
1318                         sizeof(struct mm_struct), 0,
1319                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1320 }