1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/kernel/ptrace.c 4 * 5 * (C) Copyright 1999 Linus Torvalds 6 * 7 * Common interfaces for "ptrace()" which we do not want 8 * to continually duplicate across every architecture. 9 */ 10 11 #include <linux/capability.h> 12 #include <linux/export.h> 13 #include <linux/sched.h> 14 #include <linux/sched/mm.h> 15 #include <linux/sched/coredump.h> 16 #include <linux/sched/task.h> 17 #include <linux/errno.h> 18 #include <linux/mm.h> 19 #include <linux/highmem.h> 20 #include <linux/pagemap.h> 21 #include <linux/ptrace.h> 22 #include <linux/security.h> 23 #include <linux/signal.h> 24 #include <linux/uio.h> 25 #include <linux/audit.h> 26 #include <linux/pid_namespace.h> 27 #include <linux/syscalls.h> 28 #include <linux/uaccess.h> 29 #include <linux/regset.h> 30 #include <linux/hw_breakpoint.h> 31 #include <linux/cn_proc.h> 32 #include <linux/compat.h> 33 #include <linux/sched/signal.h> 34 35 #include <asm/syscall.h> /* for syscall_get_* */ 36 37 /* 38 * Access another process' address space via ptrace. 39 * Source/target buffer must be kernel space, 40 * Do not walk the page table directly, use get_user_pages 41 */ 42 int ptrace_access_vm(struct task_struct *tsk, unsigned long addr, 43 void *buf, int len, unsigned int gup_flags) 44 { 45 struct mm_struct *mm; 46 int ret; 47 48 mm = get_task_mm(tsk); 49 if (!mm) 50 return 0; 51 52 if (!tsk->ptrace || 53 (current != tsk->parent) || 54 ((get_dumpable(mm) != SUID_DUMP_USER) && 55 !ptracer_capable(tsk, mm->user_ns))) { 56 mmput(mm); 57 return 0; 58 } 59 60 ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags); 61 mmput(mm); 62 63 return ret; 64 } 65 66 67 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent, 68 const struct cred *ptracer_cred) 69 { 70 BUG_ON(!list_empty(&child->ptrace_entry)); 71 list_add(&child->ptrace_entry, &new_parent->ptraced); 72 child->parent = new_parent; 73 child->ptracer_cred = get_cred(ptracer_cred); 74 } 75 76 /* 77 * ptrace a task: make the debugger its new parent and 78 * move it to the ptrace list. 79 * 80 * Must be called with the tasklist lock write-held. 81 */ 82 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent) 83 { 84 __ptrace_link(child, new_parent, current_cred()); 85 } 86 87 /** 88 * __ptrace_unlink - unlink ptracee and restore its execution state 89 * @child: ptracee to be unlinked 90 * 91 * Remove @child from the ptrace list, move it back to the original parent, 92 * and restore the execution state so that it conforms to the group stop 93 * state. 94 * 95 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer 96 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between 97 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. 98 * If the ptracer is exiting, the ptracee can be in any state. 99 * 100 * After detach, the ptracee should be in a state which conforms to the 101 * group stop. If the group is stopped or in the process of stopping, the 102 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken 103 * up from TASK_TRACED. 104 * 105 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, 106 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar 107 * to but in the opposite direction of what happens while attaching to a 108 * stopped task. However, in this direction, the intermediate RUNNING 109 * state is not hidden even from the current ptracer and if it immediately 110 * re-attaches and performs a WNOHANG wait(2), it may fail. 111 * 112 * CONTEXT: 113 * write_lock_irq(tasklist_lock) 114 */ 115 void __ptrace_unlink(struct task_struct *child) 116 { 117 const struct cred *old_cred; 118 BUG_ON(!child->ptrace); 119 120 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 121 #ifdef TIF_SYSCALL_EMU 122 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); 123 #endif 124 125 child->parent = child->real_parent; 126 list_del_init(&child->ptrace_entry); 127 old_cred = child->ptracer_cred; 128 child->ptracer_cred = NULL; 129 put_cred(old_cred); 130 131 spin_lock(&child->sighand->siglock); 132 child->ptrace = 0; 133 /* 134 * Clear all pending traps and TRAPPING. TRAPPING should be 135 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. 136 */ 137 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); 138 task_clear_jobctl_trapping(child); 139 140 /* 141 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and 142 * @child isn't dead. 143 */ 144 if (!(child->flags & PF_EXITING) && 145 (child->signal->flags & SIGNAL_STOP_STOPPED || 146 child->signal->group_stop_count)) { 147 child->jobctl |= JOBCTL_STOP_PENDING; 148 149 /* 150 * This is only possible if this thread was cloned by the 151 * traced task running in the stopped group, set the signal 152 * for the future reports. 153 * FIXME: we should change ptrace_init_task() to handle this 154 * case. 155 */ 156 if (!(child->jobctl & JOBCTL_STOP_SIGMASK)) 157 child->jobctl |= SIGSTOP; 158 } 159 160 /* 161 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick 162 * @child in the butt. Note that @resume should be used iff @child 163 * is in TASK_TRACED; otherwise, we might unduly disrupt 164 * TASK_KILLABLE sleeps. 165 */ 166 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) 167 ptrace_signal_wake_up(child, true); 168 169 spin_unlock(&child->sighand->siglock); 170 } 171 172 /* Ensure that nothing can wake it up, even SIGKILL */ 173 static bool ptrace_freeze_traced(struct task_struct *task) 174 { 175 bool ret = false; 176 177 /* Lockless, nobody but us can set this flag */ 178 if (task->jobctl & JOBCTL_LISTENING) 179 return ret; 180 181 spin_lock_irq(&task->sighand->siglock); 182 if (task_is_traced(task) && !__fatal_signal_pending(task)) { 183 task->state = __TASK_TRACED; 184 ret = true; 185 } 186 spin_unlock_irq(&task->sighand->siglock); 187 188 return ret; 189 } 190 191 static void ptrace_unfreeze_traced(struct task_struct *task) 192 { 193 if (task->state != __TASK_TRACED) 194 return; 195 196 WARN_ON(!task->ptrace || task->parent != current); 197 198 /* 199 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely. 200 * Recheck state under the lock to close this race. 201 */ 202 spin_lock_irq(&task->sighand->siglock); 203 if (task->state == __TASK_TRACED) { 204 if (__fatal_signal_pending(task)) 205 wake_up_state(task, __TASK_TRACED); 206 else 207 task->state = TASK_TRACED; 208 } 209 spin_unlock_irq(&task->sighand->siglock); 210 } 211 212 /** 213 * ptrace_check_attach - check whether ptracee is ready for ptrace operation 214 * @child: ptracee to check for 215 * @ignore_state: don't check whether @child is currently %TASK_TRACED 216 * 217 * Check whether @child is being ptraced by %current and ready for further 218 * ptrace operations. If @ignore_state is %false, @child also should be in 219 * %TASK_TRACED state and on return the child is guaranteed to be traced 220 * and not executing. If @ignore_state is %true, @child can be in any 221 * state. 222 * 223 * CONTEXT: 224 * Grabs and releases tasklist_lock and @child->sighand->siglock. 225 * 226 * RETURNS: 227 * 0 on success, -ESRCH if %child is not ready. 228 */ 229 static int ptrace_check_attach(struct task_struct *child, bool ignore_state) 230 { 231 int ret = -ESRCH; 232 233 /* 234 * We take the read lock around doing both checks to close a 235 * possible race where someone else was tracing our child and 236 * detached between these two checks. After this locked check, 237 * we are sure that this is our traced child and that can only 238 * be changed by us so it's not changing right after this. 239 */ 240 read_lock(&tasklist_lock); 241 if (child->ptrace && child->parent == current) { 242 WARN_ON(child->state == __TASK_TRACED); 243 /* 244 * child->sighand can't be NULL, release_task() 245 * does ptrace_unlink() before __exit_signal(). 246 */ 247 if (ignore_state || ptrace_freeze_traced(child)) 248 ret = 0; 249 } 250 read_unlock(&tasklist_lock); 251 252 if (!ret && !ignore_state) { 253 if (!wait_task_inactive(child, __TASK_TRACED)) { 254 /* 255 * This can only happen if may_ptrace_stop() fails and 256 * ptrace_stop() changes ->state back to TASK_RUNNING, 257 * so we should not worry about leaking __TASK_TRACED. 258 */ 259 WARN_ON(child->state == __TASK_TRACED); 260 ret = -ESRCH; 261 } 262 } 263 264 return ret; 265 } 266 267 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode) 268 { 269 if (mode & PTRACE_MODE_NOAUDIT) 270 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); 271 else 272 return has_ns_capability(current, ns, CAP_SYS_PTRACE); 273 } 274 275 /* Returns 0 on success, -errno on denial. */ 276 static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 277 { 278 const struct cred *cred = current_cred(), *tcred; 279 struct mm_struct *mm; 280 kuid_t caller_uid; 281 kgid_t caller_gid; 282 283 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) { 284 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n"); 285 return -EPERM; 286 } 287 288 /* May we inspect the given task? 289 * This check is used both for attaching with ptrace 290 * and for allowing access to sensitive information in /proc. 291 * 292 * ptrace_attach denies several cases that /proc allows 293 * because setting up the necessary parent/child relationship 294 * or halting the specified task is impossible. 295 */ 296 297 /* Don't let security modules deny introspection */ 298 if (same_thread_group(task, current)) 299 return 0; 300 rcu_read_lock(); 301 if (mode & PTRACE_MODE_FSCREDS) { 302 caller_uid = cred->fsuid; 303 caller_gid = cred->fsgid; 304 } else { 305 /* 306 * Using the euid would make more sense here, but something 307 * in userland might rely on the old behavior, and this 308 * shouldn't be a security problem since 309 * PTRACE_MODE_REALCREDS implies that the caller explicitly 310 * used a syscall that requests access to another process 311 * (and not a filesystem syscall to procfs). 312 */ 313 caller_uid = cred->uid; 314 caller_gid = cred->gid; 315 } 316 tcred = __task_cred(task); 317 if (uid_eq(caller_uid, tcred->euid) && 318 uid_eq(caller_uid, tcred->suid) && 319 uid_eq(caller_uid, tcred->uid) && 320 gid_eq(caller_gid, tcred->egid) && 321 gid_eq(caller_gid, tcred->sgid) && 322 gid_eq(caller_gid, tcred->gid)) 323 goto ok; 324 if (ptrace_has_cap(tcred->user_ns, mode)) 325 goto ok; 326 rcu_read_unlock(); 327 return -EPERM; 328 ok: 329 rcu_read_unlock(); 330 /* 331 * If a task drops privileges and becomes nondumpable (through a syscall 332 * like setresuid()) while we are trying to access it, we must ensure 333 * that the dumpability is read after the credentials; otherwise, 334 * we may be able to attach to a task that we shouldn't be able to 335 * attach to (as if the task had dropped privileges without becoming 336 * nondumpable). 337 * Pairs with a write barrier in commit_creds(). 338 */ 339 smp_rmb(); 340 mm = task->mm; 341 if (mm && 342 ((get_dumpable(mm) != SUID_DUMP_USER) && 343 !ptrace_has_cap(mm->user_ns, mode))) 344 return -EPERM; 345 346 return security_ptrace_access_check(task, mode); 347 } 348 349 bool ptrace_may_access(struct task_struct *task, unsigned int mode) 350 { 351 int err; 352 task_lock(task); 353 err = __ptrace_may_access(task, mode); 354 task_unlock(task); 355 return !err; 356 } 357 358 static int ptrace_attach(struct task_struct *task, long request, 359 unsigned long addr, 360 unsigned long flags) 361 { 362 bool seize = (request == PTRACE_SEIZE); 363 int retval; 364 365 retval = -EIO; 366 if (seize) { 367 if (addr != 0) 368 goto out; 369 if (flags & ~(unsigned long)PTRACE_O_MASK) 370 goto out; 371 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); 372 } else { 373 flags = PT_PTRACED; 374 } 375 376 audit_ptrace(task); 377 378 retval = -EPERM; 379 if (unlikely(task->flags & PF_KTHREAD)) 380 goto out; 381 if (same_thread_group(task, current)) 382 goto out; 383 384 /* 385 * Protect exec's credential calculations against our interference; 386 * SUID, SGID and LSM creds get determined differently 387 * under ptrace. 388 */ 389 retval = -ERESTARTNOINTR; 390 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) 391 goto out; 392 393 task_lock(task); 394 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS); 395 task_unlock(task); 396 if (retval) 397 goto unlock_creds; 398 399 write_lock_irq(&tasklist_lock); 400 retval = -EPERM; 401 if (unlikely(task->exit_state)) 402 goto unlock_tasklist; 403 if (task->ptrace) 404 goto unlock_tasklist; 405 406 if (seize) 407 flags |= PT_SEIZED; 408 task->ptrace = flags; 409 410 ptrace_link(task, current); 411 412 /* SEIZE doesn't trap tracee on attach */ 413 if (!seize) 414 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task); 415 416 spin_lock(&task->sighand->siglock); 417 418 /* 419 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 420 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 421 * will be cleared if the child completes the transition or any 422 * event which clears the group stop states happens. We'll wait 423 * for the transition to complete before returning from this 424 * function. 425 * 426 * This hides STOPPED -> RUNNING -> TRACED transition from the 427 * attaching thread but a different thread in the same group can 428 * still observe the transient RUNNING state. IOW, if another 429 * thread's WNOHANG wait(2) on the stopped tracee races against 430 * ATTACH, the wait(2) may fail due to the transient RUNNING. 431 * 432 * The following task_is_stopped() test is safe as both transitions 433 * in and out of STOPPED are protected by siglock. 434 */ 435 if (task_is_stopped(task) && 436 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) 437 signal_wake_up_state(task, __TASK_STOPPED); 438 439 spin_unlock(&task->sighand->siglock); 440 441 retval = 0; 442 unlock_tasklist: 443 write_unlock_irq(&tasklist_lock); 444 unlock_creds: 445 mutex_unlock(&task->signal->cred_guard_mutex); 446 out: 447 if (!retval) { 448 /* 449 * We do not bother to change retval or clear JOBCTL_TRAPPING 450 * if wait_on_bit() was interrupted by SIGKILL. The tracer will 451 * not return to user-mode, it will exit and clear this bit in 452 * __ptrace_unlink() if it wasn't already cleared by the tracee; 453 * and until then nobody can ptrace this task. 454 */ 455 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE); 456 proc_ptrace_connector(task, PTRACE_ATTACH); 457 } 458 459 return retval; 460 } 461 462 /** 463 * ptrace_traceme -- helper for PTRACE_TRACEME 464 * 465 * Performs checks and sets PT_PTRACED. 466 * Should be used by all ptrace implementations for PTRACE_TRACEME. 467 */ 468 static int ptrace_traceme(void) 469 { 470 int ret = -EPERM; 471 472 write_lock_irq(&tasklist_lock); 473 /* Are we already being traced? */ 474 if (!current->ptrace) { 475 ret = security_ptrace_traceme(current->parent); 476 /* 477 * Check PF_EXITING to ensure ->real_parent has not passed 478 * exit_ptrace(). Otherwise we don't report the error but 479 * pretend ->real_parent untraces us right after return. 480 */ 481 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 482 current->ptrace = PT_PTRACED; 483 ptrace_link(current, current->real_parent); 484 } 485 } 486 write_unlock_irq(&tasklist_lock); 487 488 return ret; 489 } 490 491 /* 492 * Called with irqs disabled, returns true if childs should reap themselves. 493 */ 494 static int ignoring_children(struct sighand_struct *sigh) 495 { 496 int ret; 497 spin_lock(&sigh->siglock); 498 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 499 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 500 spin_unlock(&sigh->siglock); 501 return ret; 502 } 503 504 /* 505 * Called with tasklist_lock held for writing. 506 * Unlink a traced task, and clean it up if it was a traced zombie. 507 * Return true if it needs to be reaped with release_task(). 508 * (We can't call release_task() here because we already hold tasklist_lock.) 509 * 510 * If it's a zombie, our attachedness prevented normal parent notification 511 * or self-reaping. Do notification now if it would have happened earlier. 512 * If it should reap itself, return true. 513 * 514 * If it's our own child, there is no notification to do. But if our normal 515 * children self-reap, then this child was prevented by ptrace and we must 516 * reap it now, in that case we must also wake up sub-threads sleeping in 517 * do_wait(). 518 */ 519 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 520 { 521 bool dead; 522 523 __ptrace_unlink(p); 524 525 if (p->exit_state != EXIT_ZOMBIE) 526 return false; 527 528 dead = !thread_group_leader(p); 529 530 if (!dead && thread_group_empty(p)) { 531 if (!same_thread_group(p->real_parent, tracer)) 532 dead = do_notify_parent(p, p->exit_signal); 533 else if (ignoring_children(tracer->sighand)) { 534 __wake_up_parent(p, tracer); 535 dead = true; 536 } 537 } 538 /* Mark it as in the process of being reaped. */ 539 if (dead) 540 p->exit_state = EXIT_DEAD; 541 return dead; 542 } 543 544 static int ptrace_detach(struct task_struct *child, unsigned int data) 545 { 546 if (!valid_signal(data)) 547 return -EIO; 548 549 /* Architecture-specific hardware disable .. */ 550 ptrace_disable(child); 551 552 write_lock_irq(&tasklist_lock); 553 /* 554 * We rely on ptrace_freeze_traced(). It can't be killed and 555 * untraced by another thread, it can't be a zombie. 556 */ 557 WARN_ON(!child->ptrace || child->exit_state); 558 /* 559 * tasklist_lock avoids the race with wait_task_stopped(), see 560 * the comment in ptrace_resume(). 561 */ 562 child->exit_code = data; 563 __ptrace_detach(current, child); 564 write_unlock_irq(&tasklist_lock); 565 566 proc_ptrace_connector(child, PTRACE_DETACH); 567 568 return 0; 569 } 570 571 /* 572 * Detach all tasks we were using ptrace on. Called with tasklist held 573 * for writing. 574 */ 575 void exit_ptrace(struct task_struct *tracer, struct list_head *dead) 576 { 577 struct task_struct *p, *n; 578 579 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 580 if (unlikely(p->ptrace & PT_EXITKILL)) 581 send_sig_info(SIGKILL, SEND_SIG_PRIV, p); 582 583 if (__ptrace_detach(tracer, p)) 584 list_add(&p->ptrace_entry, dead); 585 } 586 } 587 588 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 589 { 590 int copied = 0; 591 592 while (len > 0) { 593 char buf[128]; 594 int this_len, retval; 595 596 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 597 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE); 598 599 if (!retval) { 600 if (copied) 601 break; 602 return -EIO; 603 } 604 if (copy_to_user(dst, buf, retval)) 605 return -EFAULT; 606 copied += retval; 607 src += retval; 608 dst += retval; 609 len -= retval; 610 } 611 return copied; 612 } 613 614 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 615 { 616 int copied = 0; 617 618 while (len > 0) { 619 char buf[128]; 620 int this_len, retval; 621 622 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 623 if (copy_from_user(buf, src, this_len)) 624 return -EFAULT; 625 retval = ptrace_access_vm(tsk, dst, buf, this_len, 626 FOLL_FORCE | FOLL_WRITE); 627 if (!retval) { 628 if (copied) 629 break; 630 return -EIO; 631 } 632 copied += retval; 633 src += retval; 634 dst += retval; 635 len -= retval; 636 } 637 return copied; 638 } 639 640 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 641 { 642 unsigned flags; 643 644 if (data & ~(unsigned long)PTRACE_O_MASK) 645 return -EINVAL; 646 647 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { 648 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) || 649 !IS_ENABLED(CONFIG_SECCOMP)) 650 return -EINVAL; 651 652 if (!capable(CAP_SYS_ADMIN)) 653 return -EPERM; 654 655 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED || 656 current->ptrace & PT_SUSPEND_SECCOMP) 657 return -EPERM; 658 } 659 660 /* Avoid intermediate state when all opts are cleared */ 661 flags = child->ptrace; 662 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 663 flags |= (data << PT_OPT_FLAG_SHIFT); 664 child->ptrace = flags; 665 666 return 0; 667 } 668 669 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info) 670 { 671 unsigned long flags; 672 int error = -ESRCH; 673 674 if (lock_task_sighand(child, &flags)) { 675 error = -EINVAL; 676 if (likely(child->last_siginfo != NULL)) { 677 copy_siginfo(info, child->last_siginfo); 678 error = 0; 679 } 680 unlock_task_sighand(child, &flags); 681 } 682 return error; 683 } 684 685 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info) 686 { 687 unsigned long flags; 688 int error = -ESRCH; 689 690 if (lock_task_sighand(child, &flags)) { 691 error = -EINVAL; 692 if (likely(child->last_siginfo != NULL)) { 693 copy_siginfo(child->last_siginfo, info); 694 error = 0; 695 } 696 unlock_task_sighand(child, &flags); 697 } 698 return error; 699 } 700 701 static int ptrace_peek_siginfo(struct task_struct *child, 702 unsigned long addr, 703 unsigned long data) 704 { 705 struct ptrace_peeksiginfo_args arg; 706 struct sigpending *pending; 707 struct sigqueue *q; 708 int ret, i; 709 710 ret = copy_from_user(&arg, (void __user *) addr, 711 sizeof(struct ptrace_peeksiginfo_args)); 712 if (ret) 713 return -EFAULT; 714 715 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 716 return -EINVAL; /* unknown flags */ 717 718 if (arg.nr < 0) 719 return -EINVAL; 720 721 /* Ensure arg.off fits in an unsigned long */ 722 if (arg.off > ULONG_MAX) 723 return 0; 724 725 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 726 pending = &child->signal->shared_pending; 727 else 728 pending = &child->pending; 729 730 for (i = 0; i < arg.nr; ) { 731 kernel_siginfo_t info; 732 unsigned long off = arg.off + i; 733 bool found = false; 734 735 spin_lock_irq(&child->sighand->siglock); 736 list_for_each_entry(q, &pending->list, list) { 737 if (!off--) { 738 found = true; 739 copy_siginfo(&info, &q->info); 740 break; 741 } 742 } 743 spin_unlock_irq(&child->sighand->siglock); 744 745 if (!found) /* beyond the end of the list */ 746 break; 747 748 #ifdef CONFIG_COMPAT 749 if (unlikely(in_compat_syscall())) { 750 compat_siginfo_t __user *uinfo = compat_ptr(data); 751 752 if (copy_siginfo_to_user32(uinfo, &info)) { 753 ret = -EFAULT; 754 break; 755 } 756 757 } else 758 #endif 759 { 760 siginfo_t __user *uinfo = (siginfo_t __user *) data; 761 762 if (copy_siginfo_to_user(uinfo, &info)) { 763 ret = -EFAULT; 764 break; 765 } 766 } 767 768 data += sizeof(siginfo_t); 769 i++; 770 771 if (signal_pending(current)) 772 break; 773 774 cond_resched(); 775 } 776 777 if (i > 0) 778 return i; 779 780 return ret; 781 } 782 783 #ifdef PTRACE_SINGLESTEP 784 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 785 #else 786 #define is_singlestep(request) 0 787 #endif 788 789 #ifdef PTRACE_SINGLEBLOCK 790 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 791 #else 792 #define is_singleblock(request) 0 793 #endif 794 795 #ifdef PTRACE_SYSEMU 796 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 797 #else 798 #define is_sysemu_singlestep(request) 0 799 #endif 800 801 static int ptrace_resume(struct task_struct *child, long request, 802 unsigned long data) 803 { 804 bool need_siglock; 805 806 if (!valid_signal(data)) 807 return -EIO; 808 809 if (request == PTRACE_SYSCALL) 810 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 811 else 812 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 813 814 #ifdef TIF_SYSCALL_EMU 815 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 816 set_tsk_thread_flag(child, TIF_SYSCALL_EMU); 817 else 818 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); 819 #endif 820 821 if (is_singleblock(request)) { 822 if (unlikely(!arch_has_block_step())) 823 return -EIO; 824 user_enable_block_step(child); 825 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 826 if (unlikely(!arch_has_single_step())) 827 return -EIO; 828 user_enable_single_step(child); 829 } else { 830 user_disable_single_step(child); 831 } 832 833 /* 834 * Change ->exit_code and ->state under siglock to avoid the race 835 * with wait_task_stopped() in between; a non-zero ->exit_code will 836 * wrongly look like another report from tracee. 837 * 838 * Note that we need siglock even if ->exit_code == data and/or this 839 * status was not reported yet, the new status must not be cleared by 840 * wait_task_stopped() after resume. 841 * 842 * If data == 0 we do not care if wait_task_stopped() reports the old 843 * status and clears the code too; this can't race with the tracee, it 844 * takes siglock after resume. 845 */ 846 need_siglock = data && !thread_group_empty(current); 847 if (need_siglock) 848 spin_lock_irq(&child->sighand->siglock); 849 child->exit_code = data; 850 wake_up_state(child, __TASK_TRACED); 851 if (need_siglock) 852 spin_unlock_irq(&child->sighand->siglock); 853 854 return 0; 855 } 856 857 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 858 859 static const struct user_regset * 860 find_regset(const struct user_regset_view *view, unsigned int type) 861 { 862 const struct user_regset *regset; 863 int n; 864 865 for (n = 0; n < view->n; ++n) { 866 regset = view->regsets + n; 867 if (regset->core_note_type == type) 868 return regset; 869 } 870 871 return NULL; 872 } 873 874 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 875 struct iovec *kiov) 876 { 877 const struct user_regset_view *view = task_user_regset_view(task); 878 const struct user_regset *regset = find_regset(view, type); 879 int regset_no; 880 881 if (!regset || (kiov->iov_len % regset->size) != 0) 882 return -EINVAL; 883 884 regset_no = regset - view->regsets; 885 kiov->iov_len = min(kiov->iov_len, 886 (__kernel_size_t) (regset->n * regset->size)); 887 888 if (req == PTRACE_GETREGSET) 889 return copy_regset_to_user(task, view, regset_no, 0, 890 kiov->iov_len, kiov->iov_base); 891 else 892 return copy_regset_from_user(task, view, regset_no, 0, 893 kiov->iov_len, kiov->iov_base); 894 } 895 896 /* 897 * This is declared in linux/regset.h and defined in machine-dependent 898 * code. We put the export here, near the primary machine-neutral use, 899 * to ensure no machine forgets it. 900 */ 901 EXPORT_SYMBOL_GPL(task_user_regset_view); 902 903 static unsigned long 904 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs, 905 struct ptrace_syscall_info *info) 906 { 907 unsigned long args[ARRAY_SIZE(info->entry.args)]; 908 int i; 909 910 info->op = PTRACE_SYSCALL_INFO_ENTRY; 911 info->entry.nr = syscall_get_nr(child, regs); 912 syscall_get_arguments(child, regs, args); 913 for (i = 0; i < ARRAY_SIZE(args); i++) 914 info->entry.args[i] = args[i]; 915 916 /* args is the last field in struct ptrace_syscall_info.entry */ 917 return offsetofend(struct ptrace_syscall_info, entry.args); 918 } 919 920 static unsigned long 921 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs, 922 struct ptrace_syscall_info *info) 923 { 924 /* 925 * As struct ptrace_syscall_info.entry is currently a subset 926 * of struct ptrace_syscall_info.seccomp, it makes sense to 927 * initialize that subset using ptrace_get_syscall_info_entry(). 928 * This can be reconsidered in the future if these structures 929 * diverge significantly enough. 930 */ 931 ptrace_get_syscall_info_entry(child, regs, info); 932 info->op = PTRACE_SYSCALL_INFO_SECCOMP; 933 info->seccomp.ret_data = child->ptrace_message; 934 935 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */ 936 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data); 937 } 938 939 static unsigned long 940 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs, 941 struct ptrace_syscall_info *info) 942 { 943 info->op = PTRACE_SYSCALL_INFO_EXIT; 944 info->exit.rval = syscall_get_error(child, regs); 945 info->exit.is_error = !!info->exit.rval; 946 if (!info->exit.is_error) 947 info->exit.rval = syscall_get_return_value(child, regs); 948 949 /* is_error is the last field in struct ptrace_syscall_info.exit */ 950 return offsetofend(struct ptrace_syscall_info, exit.is_error); 951 } 952 953 static int 954 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, 955 void __user *datavp) 956 { 957 struct pt_regs *regs = task_pt_regs(child); 958 struct ptrace_syscall_info info = { 959 .op = PTRACE_SYSCALL_INFO_NONE, 960 .arch = syscall_get_arch(child), 961 .instruction_pointer = instruction_pointer(regs), 962 .stack_pointer = user_stack_pointer(regs), 963 }; 964 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); 965 unsigned long write_size; 966 967 /* 968 * This does not need lock_task_sighand() to access 969 * child->last_siginfo because ptrace_freeze_traced() 970 * called earlier by ptrace_check_attach() ensures that 971 * the tracee cannot go away and clear its last_siginfo. 972 */ 973 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { 974 case SIGTRAP | 0x80: 975 switch (child->ptrace_message) { 976 case PTRACE_EVENTMSG_SYSCALL_ENTRY: 977 actual_size = ptrace_get_syscall_info_entry(child, regs, 978 &info); 979 break; 980 case PTRACE_EVENTMSG_SYSCALL_EXIT: 981 actual_size = ptrace_get_syscall_info_exit(child, regs, 982 &info); 983 break; 984 } 985 break; 986 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): 987 actual_size = ptrace_get_syscall_info_seccomp(child, regs, 988 &info); 989 break; 990 } 991 992 write_size = min(actual_size, user_size); 993 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; 994 } 995 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */ 996 997 int ptrace_request(struct task_struct *child, long request, 998 unsigned long addr, unsigned long data) 999 { 1000 bool seized = child->ptrace & PT_SEIZED; 1001 int ret = -EIO; 1002 kernel_siginfo_t siginfo, *si; 1003 void __user *datavp = (void __user *) data; 1004 unsigned long __user *datalp = datavp; 1005 unsigned long flags; 1006 1007 switch (request) { 1008 case PTRACE_PEEKTEXT: 1009 case PTRACE_PEEKDATA: 1010 return generic_ptrace_peekdata(child, addr, data); 1011 case PTRACE_POKETEXT: 1012 case PTRACE_POKEDATA: 1013 return generic_ptrace_pokedata(child, addr, data); 1014 1015 #ifdef PTRACE_OLDSETOPTIONS 1016 case PTRACE_OLDSETOPTIONS: 1017 #endif 1018 case PTRACE_SETOPTIONS: 1019 ret = ptrace_setoptions(child, data); 1020 break; 1021 case PTRACE_GETEVENTMSG: 1022 ret = put_user(child->ptrace_message, datalp); 1023 break; 1024 1025 case PTRACE_PEEKSIGINFO: 1026 ret = ptrace_peek_siginfo(child, addr, data); 1027 break; 1028 1029 case PTRACE_GETSIGINFO: 1030 ret = ptrace_getsiginfo(child, &siginfo); 1031 if (!ret) 1032 ret = copy_siginfo_to_user(datavp, &siginfo); 1033 break; 1034 1035 case PTRACE_SETSIGINFO: 1036 ret = copy_siginfo_from_user(&siginfo, datavp); 1037 if (!ret) 1038 ret = ptrace_setsiginfo(child, &siginfo); 1039 break; 1040 1041 case PTRACE_GETSIGMASK: { 1042 sigset_t *mask; 1043 1044 if (addr != sizeof(sigset_t)) { 1045 ret = -EINVAL; 1046 break; 1047 } 1048 1049 if (test_tsk_restore_sigmask(child)) 1050 mask = &child->saved_sigmask; 1051 else 1052 mask = &child->blocked; 1053 1054 if (copy_to_user(datavp, mask, sizeof(sigset_t))) 1055 ret = -EFAULT; 1056 else 1057 ret = 0; 1058 1059 break; 1060 } 1061 1062 case PTRACE_SETSIGMASK: { 1063 sigset_t new_set; 1064 1065 if (addr != sizeof(sigset_t)) { 1066 ret = -EINVAL; 1067 break; 1068 } 1069 1070 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 1071 ret = -EFAULT; 1072 break; 1073 } 1074 1075 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1076 1077 /* 1078 * Every thread does recalc_sigpending() after resume, so 1079 * retarget_shared_pending() and recalc_sigpending() are not 1080 * called here. 1081 */ 1082 spin_lock_irq(&child->sighand->siglock); 1083 child->blocked = new_set; 1084 spin_unlock_irq(&child->sighand->siglock); 1085 1086 clear_tsk_restore_sigmask(child); 1087 1088 ret = 0; 1089 break; 1090 } 1091 1092 case PTRACE_INTERRUPT: 1093 /* 1094 * Stop tracee without any side-effect on signal or job 1095 * control. At least one trap is guaranteed to happen 1096 * after this request. If @child is already trapped, the 1097 * current trap is not disturbed and another trap will 1098 * happen after the current trap is ended with PTRACE_CONT. 1099 * 1100 * The actual trap might not be PTRACE_EVENT_STOP trap but 1101 * the pending condition is cleared regardless. 1102 */ 1103 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1104 break; 1105 1106 /* 1107 * INTERRUPT doesn't disturb existing trap sans one 1108 * exception. If ptracer issued LISTEN for the current 1109 * STOP, this INTERRUPT should clear LISTEN and re-trap 1110 * tracee into STOP. 1111 */ 1112 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 1113 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 1114 1115 unlock_task_sighand(child, &flags); 1116 ret = 0; 1117 break; 1118 1119 case PTRACE_LISTEN: 1120 /* 1121 * Listen for events. Tracee must be in STOP. It's not 1122 * resumed per-se but is not considered to be in TRACED by 1123 * wait(2) or ptrace(2). If an async event (e.g. group 1124 * stop state change) happens, tracee will enter STOP trap 1125 * again. Alternatively, ptracer can issue INTERRUPT to 1126 * finish listening and re-trap tracee into STOP. 1127 */ 1128 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1129 break; 1130 1131 si = child->last_siginfo; 1132 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 1133 child->jobctl |= JOBCTL_LISTENING; 1134 /* 1135 * If NOTIFY is set, it means event happened between 1136 * start of this trap and now. Trigger re-trap. 1137 */ 1138 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 1139 ptrace_signal_wake_up(child, true); 1140 ret = 0; 1141 } 1142 unlock_task_sighand(child, &flags); 1143 break; 1144 1145 case PTRACE_DETACH: /* detach a process that was attached. */ 1146 ret = ptrace_detach(child, data); 1147 break; 1148 1149 #ifdef CONFIG_BINFMT_ELF_FDPIC 1150 case PTRACE_GETFDPIC: { 1151 struct mm_struct *mm = get_task_mm(child); 1152 unsigned long tmp = 0; 1153 1154 ret = -ESRCH; 1155 if (!mm) 1156 break; 1157 1158 switch (addr) { 1159 case PTRACE_GETFDPIC_EXEC: 1160 tmp = mm->context.exec_fdpic_loadmap; 1161 break; 1162 case PTRACE_GETFDPIC_INTERP: 1163 tmp = mm->context.interp_fdpic_loadmap; 1164 break; 1165 default: 1166 break; 1167 } 1168 mmput(mm); 1169 1170 ret = put_user(tmp, datalp); 1171 break; 1172 } 1173 #endif 1174 1175 #ifdef PTRACE_SINGLESTEP 1176 case PTRACE_SINGLESTEP: 1177 #endif 1178 #ifdef PTRACE_SINGLEBLOCK 1179 case PTRACE_SINGLEBLOCK: 1180 #endif 1181 #ifdef PTRACE_SYSEMU 1182 case PTRACE_SYSEMU: 1183 case PTRACE_SYSEMU_SINGLESTEP: 1184 #endif 1185 case PTRACE_SYSCALL: 1186 case PTRACE_CONT: 1187 return ptrace_resume(child, request, data); 1188 1189 case PTRACE_KILL: 1190 if (child->exit_state) /* already dead */ 1191 return 0; 1192 return ptrace_resume(child, request, SIGKILL); 1193 1194 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1195 case PTRACE_GETREGSET: 1196 case PTRACE_SETREGSET: { 1197 struct iovec kiov; 1198 struct iovec __user *uiov = datavp; 1199 1200 if (!access_ok(uiov, sizeof(*uiov))) 1201 return -EFAULT; 1202 1203 if (__get_user(kiov.iov_base, &uiov->iov_base) || 1204 __get_user(kiov.iov_len, &uiov->iov_len)) 1205 return -EFAULT; 1206 1207 ret = ptrace_regset(child, request, addr, &kiov); 1208 if (!ret) 1209 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1210 break; 1211 } 1212 1213 case PTRACE_GET_SYSCALL_INFO: 1214 ret = ptrace_get_syscall_info(child, addr, datavp); 1215 break; 1216 #endif 1217 1218 case PTRACE_SECCOMP_GET_FILTER: 1219 ret = seccomp_get_filter(child, addr, datavp); 1220 break; 1221 1222 case PTRACE_SECCOMP_GET_METADATA: 1223 ret = seccomp_get_metadata(child, addr, datavp); 1224 break; 1225 1226 default: 1227 break; 1228 } 1229 1230 return ret; 1231 } 1232 1233 #ifndef arch_ptrace_attach 1234 #define arch_ptrace_attach(child) do { } while (0) 1235 #endif 1236 1237 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1238 unsigned long, data) 1239 { 1240 struct task_struct *child; 1241 long ret; 1242 1243 if (request == PTRACE_TRACEME) { 1244 ret = ptrace_traceme(); 1245 if (!ret) 1246 arch_ptrace_attach(current); 1247 goto out; 1248 } 1249 1250 child = find_get_task_by_vpid(pid); 1251 if (!child) { 1252 ret = -ESRCH; 1253 goto out; 1254 } 1255 1256 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1257 ret = ptrace_attach(child, request, addr, data); 1258 /* 1259 * Some architectures need to do book-keeping after 1260 * a ptrace attach. 1261 */ 1262 if (!ret) 1263 arch_ptrace_attach(child); 1264 goto out_put_task_struct; 1265 } 1266 1267 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1268 request == PTRACE_INTERRUPT); 1269 if (ret < 0) 1270 goto out_put_task_struct; 1271 1272 ret = arch_ptrace(child, request, addr, data); 1273 if (ret || request != PTRACE_DETACH) 1274 ptrace_unfreeze_traced(child); 1275 1276 out_put_task_struct: 1277 put_task_struct(child); 1278 out: 1279 return ret; 1280 } 1281 1282 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1283 unsigned long data) 1284 { 1285 unsigned long tmp; 1286 int copied; 1287 1288 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE); 1289 if (copied != sizeof(tmp)) 1290 return -EIO; 1291 return put_user(tmp, (unsigned long __user *)data); 1292 } 1293 1294 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1295 unsigned long data) 1296 { 1297 int copied; 1298 1299 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data), 1300 FOLL_FORCE | FOLL_WRITE); 1301 return (copied == sizeof(data)) ? 0 : -EIO; 1302 } 1303 1304 #if defined CONFIG_COMPAT 1305 1306 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1307 compat_ulong_t addr, compat_ulong_t data) 1308 { 1309 compat_ulong_t __user *datap = compat_ptr(data); 1310 compat_ulong_t word; 1311 kernel_siginfo_t siginfo; 1312 int ret; 1313 1314 switch (request) { 1315 case PTRACE_PEEKTEXT: 1316 case PTRACE_PEEKDATA: 1317 ret = ptrace_access_vm(child, addr, &word, sizeof(word), 1318 FOLL_FORCE); 1319 if (ret != sizeof(word)) 1320 ret = -EIO; 1321 else 1322 ret = put_user(word, datap); 1323 break; 1324 1325 case PTRACE_POKETEXT: 1326 case PTRACE_POKEDATA: 1327 ret = ptrace_access_vm(child, addr, &data, sizeof(data), 1328 FOLL_FORCE | FOLL_WRITE); 1329 ret = (ret != sizeof(data) ? -EIO : 0); 1330 break; 1331 1332 case PTRACE_GETEVENTMSG: 1333 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1334 break; 1335 1336 case PTRACE_GETSIGINFO: 1337 ret = ptrace_getsiginfo(child, &siginfo); 1338 if (!ret) 1339 ret = copy_siginfo_to_user32( 1340 (struct compat_siginfo __user *) datap, 1341 &siginfo); 1342 break; 1343 1344 case PTRACE_SETSIGINFO: 1345 ret = copy_siginfo_from_user32( 1346 &siginfo, (struct compat_siginfo __user *) datap); 1347 if (!ret) 1348 ret = ptrace_setsiginfo(child, &siginfo); 1349 break; 1350 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1351 case PTRACE_GETREGSET: 1352 case PTRACE_SETREGSET: 1353 { 1354 struct iovec kiov; 1355 struct compat_iovec __user *uiov = 1356 (struct compat_iovec __user *) datap; 1357 compat_uptr_t ptr; 1358 compat_size_t len; 1359 1360 if (!access_ok(uiov, sizeof(*uiov))) 1361 return -EFAULT; 1362 1363 if (__get_user(ptr, &uiov->iov_base) || 1364 __get_user(len, &uiov->iov_len)) 1365 return -EFAULT; 1366 1367 kiov.iov_base = compat_ptr(ptr); 1368 kiov.iov_len = len; 1369 1370 ret = ptrace_regset(child, request, addr, &kiov); 1371 if (!ret) 1372 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1373 break; 1374 } 1375 #endif 1376 1377 default: 1378 ret = ptrace_request(child, request, addr, data); 1379 } 1380 1381 return ret; 1382 } 1383 1384 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 1385 compat_long_t, addr, compat_long_t, data) 1386 { 1387 struct task_struct *child; 1388 long ret; 1389 1390 if (request == PTRACE_TRACEME) { 1391 ret = ptrace_traceme(); 1392 goto out; 1393 } 1394 1395 child = find_get_task_by_vpid(pid); 1396 if (!child) { 1397 ret = -ESRCH; 1398 goto out; 1399 } 1400 1401 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1402 ret = ptrace_attach(child, request, addr, data); 1403 /* 1404 * Some architectures need to do book-keeping after 1405 * a ptrace attach. 1406 */ 1407 if (!ret) 1408 arch_ptrace_attach(child); 1409 goto out_put_task_struct; 1410 } 1411 1412 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1413 request == PTRACE_INTERRUPT); 1414 if (!ret) { 1415 ret = compat_arch_ptrace(child, request, addr, data); 1416 if (ret || request != PTRACE_DETACH) 1417 ptrace_unfreeze_traced(child); 1418 } 1419 1420 out_put_task_struct: 1421 put_task_struct(child); 1422 out: 1423 return ret; 1424 } 1425 #endif /* CONFIG_COMPAT */ 1426