use roland's auto-updated patches for utrace/tracehook

1 files changed, 1978 insertions, 0 deletions

diff --git a/linux-2.6-utrace-ptrace.patch b/linux-2.6-utrace-ptrace.patch
new file mode 100644
index 000000000..a609fb628
--- /dev/null
+++ b/linux-2.6-utrace-ptrace.patch
@@ -0,0 +1,1978 @@
+implement utrace-ptrace
+
+The patch adds the new file, kernel/ptrace-utrace.c, which contains
+the new implementation of ptrace over utrace.
+
+This file is not compiled until we have CONFIG_UTRACE option, will be
+added by the next "utrace core" patch.
+
+It's supposed to be an invisible implementation change, nothing should
+change to userland when CONFIG_UTRACE is enabled.
+
+Signed-off-by: Roland McGrath <roland@redhat.com>
+Signed-off-by: Oleg Nesterov <oleg@redhat.com>
+---
+ include/linux/ptrace.h |    2 +-
+ kernel/Makefile        |    1 +
+ kernel/ptrace-utrace.c | 1138 ++++++++++++++++++++++++++++++++++++++++++++++++
+ kernel/ptrace.c        |  688 ++++++++++++++---------------
+ kernel/utrace.c        |   16 +
+ 5 files changed, 1494 insertions(+), 351 deletions(-)
+
+diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
+index a85fb41..235c1b0 100644  
+--- a/include/linux/ptrace.h
++++ b/include/linux/ptrace.h
+@@ -99,7 +99,7 @@
+ #include <linux/compiler.h>		/* For unlikely.  */
+ #include <linux/sched.h>		/* For struct task_struct.  */
+ 
+-
++extern void ptrace_notify_stop(struct task_struct *tracee);
+ extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
+ extern int ptrace_traceme(void);
+ extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
+diff --git a/kernel/Makefile b/kernel/Makefile
+index 6004913..b09c9a5 100644  
+--- a/kernel/Makefile
++++ b/kernel/Makefile
+@@ -71,6 +71,7 @@ obj-$(CONFIG_RESOURCE_COUNTERS) += res_c
+ obj-$(CONFIG_SMP) += stop_machine.o
+ obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
+ obj-$(CONFIG_UTRACE) += utrace.o
++obj-$(CONFIG_UTRACE) += ptrace-utrace.o
+ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
+ obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
+ obj-$(CONFIG_AUDIT_WATCH) += audit_watch.o
+diff --git a/kernel/ptrace-utrace.c b/kernel/ptrace-utrace.c
+new file mode 100644
+index ...a90078d 100644  
+--- /dev/null
++++ b/kernel/ptrace-utrace.c
+@@ -0,0 +1,1138 @@
++/*
++ * linux/kernel/ptrace.c
++ *
++ * (C) Copyright 1999 Linus Torvalds
++ *
++ * Common interfaces for "ptrace()" which we do not want
++ * to continually duplicate across every architecture.
++ */
++
++#include <linux/capability.h>
++#include <linux/module.h>
++#include <linux/sched.h>
++#include <linux/errno.h>
++#include <linux/mm.h>
++#include <linux/highmem.h>
++#include <linux/pagemap.h>
++#include <linux/smp_lock.h>
++#include <linux/ptrace.h>
++#include <linux/utrace.h>
++#include <linux/security.h>
++#include <linux/signal.h>
++#include <linux/audit.h>
++#include <linux/pid_namespace.h>
++#include <linux/syscalls.h>
++#include <linux/uaccess.h>
++
++/*
++ * ptrace a task: make the debugger its new parent and
++ * move it to the ptrace list.
++ *
++ * Must be called with the tasklist lock write-held.
++ */
++void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
++{
++	BUG_ON(!list_empty(&child->ptrace_entry));
++	list_add(&child->ptrace_entry, &new_parent->ptraced);
++	child->parent = new_parent;
++}
++
++/*
++ * unptrace a task: move it back to its original parent and
++ * remove it from the ptrace list.
++ *
++ * Must be called with the tasklist lock write-held.
++ */
++void __ptrace_unlink(struct task_struct *child)
++{
++	BUG_ON(!child->ptrace);
++
++	child->ptrace = 0;
++	child->parent = child->real_parent;
++	list_del_init(&child->ptrace_entry);
++}
++
++struct ptrace_context {
++	int				options;
++
++	int				signr;
++	siginfo_t			*siginfo;
++
++	int				stop_code;
++	unsigned long			eventmsg;
++
++	enum utrace_resume_action	resume;
++};
++
++#define PT_UTRACED			0x00001000
++
++#define PTRACE_O_SYSEMU			0x100
++
++#define PTRACE_EVENT_SYSCALL		(1 << 16)
++#define PTRACE_EVENT_SIGTRAP		(2 << 16)
++#define PTRACE_EVENT_SIGNAL		(3 << 16)
++/* events visible to user-space */
++#define PTRACE_EVENT_MASK		0xFFFF
++
++static inline bool ptrace_event_pending(struct ptrace_context *ctx)
++{
++	return ctx->stop_code != 0;
++}
++
++static inline int get_stop_event(struct ptrace_context *ctx)
++{
++	return ctx->stop_code >> 8;
++}
++
++static inline void set_stop_code(struct ptrace_context *ctx, int event)
++{
++	ctx->stop_code = (event << 8) | SIGTRAP;
++}
++
++static inline struct ptrace_context *
++ptrace_context(struct utrace_engine *engine)
++{
++	return engine->data;
++}
++
++static const struct utrace_engine_ops ptrace_utrace_ops; /* forward decl */
++
++static struct utrace_engine *ptrace_lookup_engine(struct task_struct *tracee)
++{
++	return utrace_attach_task(tracee, UTRACE_ATTACH_MATCH_OPS,
++					&ptrace_utrace_ops, NULL);
++}
++
++static struct utrace_engine *
++ptrace_reuse_engine(struct task_struct *tracee)
++{
++	struct utrace_engine *engine;
++	struct ptrace_context *ctx;
++	int err = -EPERM;
++
++	engine = ptrace_lookup_engine(tracee);
++	if (IS_ERR(engine))
++		return engine;
++
++	ctx = ptrace_context(engine);
++	if (unlikely(ctx->resume == UTRACE_DETACH)) {
++		/*
++		 * Try to reuse this self-detaching engine.
++		 * The only caller which can hit this case is ptrace_attach(),
++		 * it holds ->cred_guard_mutex.
++		 */
++		ctx->options = 0;
++		ctx->eventmsg = 0;
++
++		/* make sure we don't get unwanted reports */
++		err = utrace_set_events(tracee, engine, UTRACE_EVENT(QUIESCE));
++		if (!err || err == -EINPROGRESS) {
++			ctx->resume = UTRACE_RESUME;
++			/* synchronize with ptrace_report_signal() */
++			err = utrace_barrier(tracee, engine);
++		}
++		WARN_ON(!err != (engine->ops == &ptrace_utrace_ops));
++
++		if (!err)
++			return engine;
++	}
++
++	utrace_engine_put(engine);
++	return ERR_PTR(err);
++}
++
++static struct utrace_engine *
++ptrace_attach_engine(struct task_struct *tracee)
++{
++	struct utrace_engine *engine;
++	struct ptrace_context *ctx;
++
++	if (unlikely(task_utrace_flags(tracee))) {
++		engine = ptrace_reuse_engine(tracee);
++		if (!IS_ERR(engine) || IS_ERR(engine) == -EPERM)
++			return engine;
++	}
++
++	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
++	if (unlikely(!ctx))
++		return ERR_PTR(-ENOMEM);
++
++	ctx->resume = UTRACE_RESUME;
++
++	engine = utrace_attach_task(tracee, UTRACE_ATTACH_CREATE |
++						UTRACE_ATTACH_EXCLUSIVE |
++						UTRACE_ATTACH_MATCH_OPS,
++						&ptrace_utrace_ops, ctx);
++	if (unlikely(IS_ERR(engine))) {
++		if (engine != ERR_PTR(-ESRCH) &&
++		    engine != ERR_PTR(-ERESTARTNOINTR))
++			engine = ERR_PTR(-EPERM);
++		kfree(ctx);
++	}
++
++	return engine;
++}
++
++static inline int ptrace_set_events(struct task_struct *target,
++					struct utrace_engine *engine,
++					unsigned long options)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++	/*
++	 * We need QUIESCE for resume handling, CLONE to check
++	 * for CLONE_PTRACE, other events are always reported.
++	 */
++	unsigned long events = UTRACE_EVENT(QUIESCE) | UTRACE_EVENT(CLONE) |
++			       UTRACE_EVENT(EXEC) | UTRACE_EVENT_SIGNAL_ALL;
++
++	ctx->options = options;
++	if (options & PTRACE_O_TRACEEXIT)
++		events |= UTRACE_EVENT(EXIT);
++
++	return utrace_set_events(target, engine, events);
++}
++
++/*
++ * Attach a utrace engine for ptrace and set up its event mask.
++ * Returns error code or 0 on success.
++ */
++static int ptrace_attach_task(struct task_struct *tracee, int options)
++{
++	struct utrace_engine *engine;
++	int err;
++
++	engine = ptrace_attach_engine(tracee);
++	if (IS_ERR(engine))
++		return PTR_ERR(engine);
++	/*
++	 * It can fail only if the tracee is dead, the caller
++	 * must notice this before setting PT_UTRACED.
++	 */
++	err = ptrace_set_events(tracee, engine, options);
++	WARN_ON(err && !tracee->exit_state);
++	utrace_engine_put(engine);
++	return 0;
++}
++
++static int ptrace_wake_up(struct task_struct *tracee,
++				struct utrace_engine *engine,
++				enum utrace_resume_action action,
++				bool force_wakeup)
++{
++	if (force_wakeup) {
++		unsigned long flags;
++		/*
++		 * Preserve the compatibility bug. Historically ptrace
++		 * wakes up the tracee even if it should not. Clear
++		 * SIGNAL_STOP_STOPPED for utrace_wakeup().
++		 */
++		if (lock_task_sighand(tracee, &flags)) {
++			tracee->signal->flags &= ~SIGNAL_STOP_STOPPED;
++			unlock_task_sighand(tracee, &flags);
++		}
++	}
++
++	if (action != UTRACE_REPORT)
++		ptrace_context(engine)->stop_code = 0;
++
++	return utrace_control(tracee, engine, action);
++}
++
++static void ptrace_detach_task(struct task_struct *tracee, int sig)
++{
++	/*
++	 * If true, the caller is PTRACE_DETACH, otherwise
++	 * the tracer detaches implicitly during exit.
++	 */
++	bool voluntary = (sig >= 0);
++	struct utrace_engine *engine = ptrace_lookup_engine(tracee);
++	enum utrace_resume_action action = UTRACE_DETACH;
++
++	if (unlikely(IS_ERR(engine)))
++		return;
++
++	if (sig) {
++		struct ptrace_context *ctx = ptrace_context(engine);
++
++		switch (get_stop_event(ctx)) {
++		case PTRACE_EVENT_SYSCALL:
++			if (voluntary)
++				send_sig_info(sig, SEND_SIG_PRIV, tracee);
++			break;
++
++		case PTRACE_EVENT_SIGNAL:
++			if (voluntary)
++				ctx->signr = sig;
++			ctx->resume = UTRACE_DETACH;
++			action = UTRACE_RESUME;
++			break;
++		}
++	}
++
++	ptrace_wake_up(tracee, engine, action, voluntary);
++	utrace_engine_put(engine);
++}
++
++static void ptrace_abort_attach(struct task_struct *tracee)
++{
++	ptrace_detach_task(tracee, 0);
++}
++
++static u32 ptrace_report_exit(u32 action, struct utrace_engine *engine,
++			      long orig_code, long *code)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++
++	WARN_ON(ptrace_event_pending(ctx) &&
++		!signal_group_exit(current->signal));
++
++	set_stop_code(ctx, PTRACE_EVENT_EXIT);
++	ctx->eventmsg = *code;
++
++	return UTRACE_STOP;
++}
++
++static void ptrace_clone_attach(struct task_struct *child,
++				int options)
++{
++	struct task_struct *parent = current;
++	struct task_struct *tracer;
++	bool abort = true;
++
++	if (unlikely(ptrace_attach_task(child, options))) {
++		WARN_ON(1);
++		return;
++	}
++
++	write_lock_irq(&tasklist_lock);
++	tracer = parent->parent;
++	if (!(tracer->flags & PF_EXITING) && parent->ptrace) {
++		child->ptrace = parent->ptrace;
++		__ptrace_link(child, tracer);
++		abort = false;
++	}
++	write_unlock_irq(&tasklist_lock);
++	if (unlikely(abort)) {
++		ptrace_abort_attach(child);
++		return;
++	}
++
++	sigaddset(&child->pending.signal, SIGSTOP);
++	set_tsk_thread_flag(child, TIF_SIGPENDING);
++}
++
++static u32 ptrace_report_clone(u32 action, struct utrace_engine *engine,
++			       unsigned long clone_flags,
++			       struct task_struct *child)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++	int event = 0;
++
++	WARN_ON(ptrace_event_pending(ctx));
++
++	if (clone_flags & CLONE_UNTRACED) {
++		/* no events reported */
++	} else if (clone_flags & CLONE_VFORK) {
++		if (ctx->options & PTRACE_O_TRACEVFORK)
++			event = PTRACE_EVENT_VFORK;
++		else if (ctx->options & PTRACE_O_TRACEVFORKDONE)
++			event = PTRACE_EVENT_VFORK_DONE;
++	} else if ((clone_flags & CSIGNAL) != SIGCHLD) {
++		if (ctx->options & PTRACE_O_TRACECLONE)
++			event = PTRACE_EVENT_CLONE;
++	} else if (ctx->options & PTRACE_O_TRACEFORK) {
++		event = PTRACE_EVENT_FORK;
++	}
++	/*
++	 * Any of these reports implies auto-attaching the new child.
++	 * So does CLONE_PTRACE, even with no event to report.
++	 */
++	if ((event && event != PTRACE_EVENT_VFORK_DONE) ||
++				(clone_flags & CLONE_PTRACE))
++		ptrace_clone_attach(child, ctx->options);
++
++	if (!event)
++		return UTRACE_RESUME;
++
++	set_stop_code(ctx, event);
++	ctx->eventmsg = child->pid;
++	/*
++	 * We shouldn't stop now, inside the do_fork() path.
++	 * We will stop later, before return to user-mode.
++	 */
++	if (event == PTRACE_EVENT_VFORK_DONE)
++		return UTRACE_REPORT;
++	else
++		return UTRACE_STOP;
++}
++
++static inline void set_syscall_code(struct ptrace_context *ctx)
++{
++	set_stop_code(ctx, PTRACE_EVENT_SYSCALL);
++	if (ctx->options & PTRACE_O_TRACESYSGOOD)
++		ctx->stop_code |= 0x80;
++}
++
++static u32 ptrace_report_syscall_entry(u32 action, struct utrace_engine *engine,
++				       struct pt_regs *regs)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++
++	if (action & UTRACE_SYSCALL_RESUMED) {
++		/*
++		 * We already reported the first time.
++		 * Nothing more to do now.
++		 */
++		if (unlikely(ctx->options & PTRACE_O_SYSEMU))
++			return UTRACE_SYSCALL_ABORT | UTRACE_REPORT;
++		return utrace_syscall_action(action) | UTRACE_RESUME;
++	}
++
++	WARN_ON(ptrace_event_pending(ctx));
++
++	set_syscall_code(ctx);
++
++	if (unlikely(ctx->options & PTRACE_O_SYSEMU))
++		return UTRACE_SYSCALL_ABORT | UTRACE_REPORT;
++	/*
++	 * Stop now to report.  We will get another callback after
++	 * we resume, with the UTRACE_SYSCALL_RESUMED flag set.
++	 */
++	return UTRACE_SYSCALL_RUN | UTRACE_STOP;
++}
++
++static u32 ptrace_report_syscall_exit(u32 action, struct utrace_engine *engine,
++				      struct pt_regs *regs)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++
++	if (ptrace_event_pending(ctx))
++		return UTRACE_STOP;
++
++	if (ctx->resume != UTRACE_RESUME) {
++		WARN_ON(ctx->resume != UTRACE_BLOCKSTEP &&
++			ctx->resume != UTRACE_SINGLESTEP);
++		ctx->resume = UTRACE_RESUME;
++
++		ctx->signr = SIGTRAP;
++		return UTRACE_INTERRUPT;
++	}
++
++	set_syscall_code(ctx);
++	return UTRACE_STOP;
++}
++
++static u32 ptrace_report_exec(u32 action, struct utrace_engine *engine,
++			      const struct linux_binfmt *fmt,
++			      const struct linux_binprm *bprm,
++			      struct pt_regs *regs)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++
++	WARN_ON(ptrace_event_pending(ctx));
++
++	if (!(ctx->options & PTRACE_O_TRACEEXEC)) {
++		/*
++		 * Old-fashioned ptrace'd exec just posts a plain signal.
++		 */
++		send_sig(SIGTRAP, current, 0);
++		return UTRACE_RESUME;
++	}
++
++	set_stop_code(ctx, PTRACE_EVENT_EXEC);
++	return UTRACE_STOP;
++}
++
++static enum utrace_signal_action resume_signal(struct ptrace_context *ctx,
++					       struct k_sigaction *return_ka)
++{
++	siginfo_t *info = ctx->siginfo;
++	int signr = ctx->signr;
++
++	ctx->siginfo = NULL;
++	ctx->signr = 0;
++
++	/* Did the debugger cancel the sig? */
++	if (!signr)
++		return UTRACE_SIGNAL_IGN;
++	/*
++	 * Update the siginfo structure if the signal has changed.
++	 * If the debugger wanted something specific in the siginfo
++	 * then it should have updated *info via PTRACE_SETSIGINFO.
++	 */
++	if (info->si_signo != signr) {
++		info->si_signo = signr;
++		info->si_errno = 0;
++		info->si_code = SI_USER;
++		info->si_pid = task_pid_vnr(current->parent);
++		info->si_uid = task_uid(current->parent);
++	}
++
++	/* If the (new) signal is now blocked, requeue it. */
++	if (sigismember(&current->blocked, signr)) {
++		send_sig_info(signr, info, current);
++		return UTRACE_SIGNAL_IGN;
++	}
++
++	spin_lock_irq(&current->sighand->siglock);
++	*return_ka = current->sighand->action[signr - 1];
++	spin_unlock_irq(&current->sighand->siglock);
++
++	return UTRACE_SIGNAL_DELIVER;
++}
++
++static u32 ptrace_report_signal(u32 action, struct utrace_engine *engine,
++				struct pt_regs *regs,
++				siginfo_t *info,
++				const struct k_sigaction *orig_ka,
++				struct k_sigaction *return_ka)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++	enum utrace_resume_action resume = ctx->resume;
++
++	if (ptrace_event_pending(ctx)) {
++		action = utrace_signal_action(action);
++		WARN_ON(action != UTRACE_SIGNAL_REPORT);
++		return action | UTRACE_STOP;
++	}
++
++	switch (utrace_signal_action(action)) {
++	case UTRACE_SIGNAL_HANDLER:
++		if (WARN_ON(ctx->siginfo))
++			ctx->siginfo = NULL;
++
++		if (resume != UTRACE_RESUME) {
++			WARN_ON(resume != UTRACE_BLOCKSTEP &&
++				resume != UTRACE_SINGLESTEP);
++
++			set_stop_code(ctx, PTRACE_EVENT_SIGTRAP);
++			return UTRACE_STOP | UTRACE_SIGNAL_IGN;
++		}
++
++	case UTRACE_SIGNAL_REPORT:
++		if (!ctx->siginfo) {
++			if (ctx->signr) {
++				/* set by ptrace_resume(SYSCALL_EXIT) */
++				WARN_ON(ctx->signr != SIGTRAP);
++				user_single_step_siginfo(current, regs, info);
++				force_sig_info(SIGTRAP, info, current);
++			}
++
++			return resume | UTRACE_SIGNAL_IGN;
++		}
++
++		if (WARN_ON(ctx->siginfo != info))
++			return resume | UTRACE_SIGNAL_IGN;
++
++		return resume | resume_signal(ctx, return_ka);
++
++	default:
++		break;
++	}
++
++	WARN_ON(ctx->siginfo);
++	ctx->siginfo = info;
++	/*
++	 * ctx->siginfo points to the caller's stack.
++	 * Make sure the subsequent UTRACE_SIGNAL_REPORT clears
++	 * ->siginfo before return from get_signal_to_deliver().
++	 */
++	if (utrace_control(current, engine, UTRACE_INTERRUPT))
++		WARN_ON(1);
++
++	ctx->signr = info->si_signo;
++	ctx->stop_code = (PTRACE_EVENT_SIGNAL << 8) | ctx->signr;
++
++	return UTRACE_STOP | UTRACE_SIGNAL_IGN;
++}
++
++static u32 ptrace_report_quiesce(u32 action, struct utrace_engine *engine,
++				 unsigned long event)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++
++	if (ptrace_event_pending(ctx))
++		return UTRACE_STOP;
++
++	return event ? UTRACE_RESUME : ctx->resume;
++}
++
++static void ptrace_release(void *data)
++{
++	kfree(data);
++}
++
++static const struct utrace_engine_ops ptrace_utrace_ops = {
++	.report_signal = ptrace_report_signal,
++	.report_quiesce = ptrace_report_quiesce,
++	.report_exec = ptrace_report_exec,
++	.report_exit = ptrace_report_exit,
++	.report_clone = ptrace_report_clone,
++	.report_syscall_entry = ptrace_report_syscall_entry,
++	.report_syscall_exit = ptrace_report_syscall_exit,
++	.release = ptrace_release,
++};
++
++int ptrace_check_attach(struct task_struct *child, int kill)
++{
++	struct utrace_engine *engine;
++	struct utrace_examiner exam;
++	int ret = -ESRCH;
++
++	engine = ptrace_lookup_engine(child);
++	if (IS_ERR(engine))
++		return ret;
++
++	if (child->parent != current)
++		goto out;
++
++	if (unlikely(kill))
++		ret = 0;
++
++	if (!task_is_stopped_or_traced(child))
++		goto out;
++	/*
++	 * Make sure our engine has already stopped the child.
++	 * Then wait for it to be off the CPU.
++	 */
++	if (!utrace_control(child, engine, UTRACE_STOP) &&
++	    !utrace_prepare_examine(child, engine, &exam))
++		ret = 0;
++out:
++	utrace_engine_put(engine);
++	return ret;
++}
++
++int ptrace_attach(struct task_struct *task)
++{
++	int retval;
++
++	audit_ptrace(task);
++
++	retval = -EPERM;
++	if (unlikely(task->flags & PF_KTHREAD))
++		goto out;
++	if (same_thread_group(task, current))
++		goto out;
++
++	/*
++	 * Protect exec's credential calculations against our interference;
++	 * interference; SUID, SGID and LSM creds get determined differently
++	 * under ptrace.
++	 */
++	retval = -ERESTARTNOINTR;
++	if (mutex_lock_interruptible(&task->cred_guard_mutex))
++		goto out;
++
++	task_lock(task);
++	retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
++	task_unlock(task);
++	if (retval)
++		goto unlock_creds;
++
++	retval = ptrace_attach_task(task, 0);
++	if (unlikely(retval))
++		goto unlock_creds;
++
++	write_lock_irq(&tasklist_lock);
++	retval = -EPERM;
++	if (unlikely(task->exit_state))
++		goto unlock_tasklist;
++
++	BUG_ON(task->ptrace);
++	task->ptrace = PT_UTRACED;
++	if (capable(CAP_SYS_PTRACE))
++		task->ptrace |= PT_PTRACE_CAP;
++
++	__ptrace_link(task, current);
++	send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
++
++	retval = 0;
++unlock_tasklist:
++	write_unlock_irq(&tasklist_lock);
++unlock_creds:
++	mutex_unlock(&task->cred_guard_mutex);
++out:
++	return retval;
++}
++
++/*
++ * Performs checks and sets PT_UTRACED.
++ * Should be used by all ptrace implementations for PTRACE_TRACEME.
++ */
++int ptrace_traceme(void)
++{
++	bool detach = true;
++	int ret = ptrace_attach_task(current, 0);
++
++	if (unlikely(ret))
++		return ret;
++
++	ret = -EPERM;
++	write_lock_irq(&tasklist_lock);
++	BUG_ON(current->ptrace);
++	ret = security_ptrace_traceme(current->parent);
++	/*
++	 * Check PF_EXITING to ensure ->real_parent has not passed
++	 * exit_ptrace(). Otherwise we don't report the error but
++	 * pretend ->real_parent untraces us right after return.
++	 */
++	if (!ret && !(current->real_parent->flags & PF_EXITING)) {
++		current->ptrace = PT_UTRACED;
++		__ptrace_link(current, current->real_parent);
++		detach = false;
++	}
++	write_unlock_irq(&tasklist_lock);
++
++	if (detach)
++		ptrace_abort_attach(current);
++	return ret;
++}
++
++static void ptrace_do_detach(struct task_struct *tracee, unsigned int data)
++{
++	bool detach, release;
++
++	write_lock_irq(&tasklist_lock);
++	/*
++	 * This tracee can be already killed. Make sure de_thread() or
++	 * our sub-thread doing do_wait() didn't do release_task() yet.
++	 */
++	detach = tracee->ptrace != 0;
++	release = false;
++	if (likely(detach))
++		release = __ptrace_detach(current, tracee);
++	write_unlock_irq(&tasklist_lock);
++
++	if (unlikely(release))
++		release_task(tracee);
++	else if (likely(detach))
++		ptrace_detach_task(tracee, data);
++}
++
++int ptrace_detach(struct task_struct *child, unsigned int data)
++{
++	if (!valid_signal(data))
++		return -EIO;
++
++	ptrace_do_detach(child, data);
++
++	return 0;
++}
++
++/*
++ * Detach all tasks we were using ptrace on. Called with tasklist held
++ * for writing, and returns with it held too. But note it can release
++ * and reacquire the lock.
++ */
++void exit_ptrace(struct task_struct *tracer)
++{
++	bool locked = true;
++
++	for (;;) {
++		struct task_struct *tracee = NULL;
++
++		if (!locked)
++			read_lock(&tasklist_lock);
++		if (!list_empty(&tracer->ptraced)) {
++			tracee = list_first_entry(&tracer->ptraced,
++					struct task_struct, ptrace_entry);
++			get_task_struct(tracee);
++		}
++		if (!locked)
++			read_unlock(&tasklist_lock);
++		if (!tracee)
++			break;
++
++		if (locked) {
++			write_unlock_irq(&tasklist_lock);
++			locked = false;
++		}
++		ptrace_do_detach(tracee, -1);
++		put_task_struct(tracee);
++	}
++
++	if (!locked)
++		write_lock_irq(&tasklist_lock);
++}
++
++static int ptrace_set_options(struct task_struct *tracee,
++				struct utrace_engine *engine, long data)
++{
++	BUILD_BUG_ON(PTRACE_O_MASK & PTRACE_O_SYSEMU);
++
++	ptrace_set_events(tracee, engine, data & PTRACE_O_MASK);
++	return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
++}
++
++static int ptrace_rw_siginfo(struct task_struct *tracee,
++				struct ptrace_context *ctx,
++				siginfo_t *info, bool write)
++{
++	unsigned long flags;
++	int err;
++
++	switch (get_stop_event(ctx)) {
++	case 0: /* jctl stop */
++		return -EINVAL;
++
++	case PTRACE_EVENT_SIGNAL:
++		err = -ESRCH;
++		if (lock_task_sighand(tracee, &flags)) {
++			if (likely(task_is_traced(tracee))) {
++				if (write)
++					*ctx->siginfo = *info;
++				else
++					*info = *ctx->siginfo;
++				err = 0;
++			}
++			unlock_task_sighand(tracee, &flags);
++		}
++
++		return err;
++
++	default:
++		if (!write) {
++			memset(info, 0, sizeof(*info));
++			info->si_signo = SIGTRAP;
++			info->si_code = ctx->stop_code & PTRACE_EVENT_MASK;
++			info->si_pid = task_pid_vnr(tracee);
++			info->si_uid = task_uid(tracee);
++		}
++
++		return 0;
++	}
++}
++
++static void do_ptrace_notify_stop(struct ptrace_context *ctx,
++					struct task_struct *tracee)
++{
++	/*
++	 * This can race with SIGKILL, but we borrow this race from
++	 * the old ptrace implementation. ->exit_code is only needed
++	 * for wait_task_stopped()->task_stopped_code(), we should
++	 * change it to use ptrace_context.
++	 */
++	tracee->exit_code = ctx->stop_code & PTRACE_EVENT_MASK;
++	WARN_ON(!tracee->exit_code);
++
++	read_lock(&tasklist_lock);
++	/*
++	 * Don't want to allow preemption here, because
++	 * sys_ptrace() needs this task to be inactive.
++	 */
++	preempt_disable();
++	/*
++	 * It can be killed and then released by our subthread,
++	 * or ptrace_attach() has not completed yet.
++	 */
++	if (task_ptrace(tracee))
++		do_notify_parent_cldstop(tracee, CLD_TRAPPED);
++	read_unlock(&tasklist_lock);
++	preempt_enable_no_resched();
++}
++
++void ptrace_notify_stop(struct task_struct *tracee)
++{
++	struct utrace_engine *engine = ptrace_lookup_engine(tracee);
++
++	if (IS_ERR(engine))
++		return;
++
++	do_ptrace_notify_stop(ptrace_context(engine), tracee);
++	utrace_engine_put(engine);
++}
++
++static int ptrace_resume_action(struct task_struct *tracee,
++				struct utrace_engine *engine, long request)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++	unsigned long events;
++	int action;
++
++	ctx->options &= ~PTRACE_O_SYSEMU;
++	events = engine->flags & ~UTRACE_EVENT_SYSCALL;
++	action = UTRACE_RESUME;
++
++	switch (request) {
++#ifdef PTRACE_SINGLEBLOCK
++	case PTRACE_SINGLEBLOCK:
++		if (unlikely(!arch_has_block_step()))
++			return -EIO;
++		action = UTRACE_BLOCKSTEP;
++		events |= UTRACE_EVENT(SYSCALL_EXIT);
++		break;
++#endif
++
++#ifdef PTRACE_SINGLESTEP
++	case PTRACE_SINGLESTEP:
++		if (unlikely(!arch_has_single_step()))
++			return -EIO;
++		action = UTRACE_SINGLESTEP;
++		events |= UTRACE_EVENT(SYSCALL_EXIT);
++		break;
++#endif
++
++#ifdef PTRACE_SYSEMU
++	case PTRACE_SYSEMU_SINGLESTEP:
++		if (unlikely(!arch_has_single_step()))
++			return -EIO;
++		action = UTRACE_SINGLESTEP;
++	case PTRACE_SYSEMU:
++		ctx->options |= PTRACE_O_SYSEMU;
++		events |= UTRACE_EVENT(SYSCALL_ENTRY);
++		break;
++#endif
++
++	case PTRACE_SYSCALL:
++		events |= UTRACE_EVENT_SYSCALL;
++		break;
++
++	case PTRACE_CONT:
++		break;
++	default:
++		return -EIO;
++	}
++
++	if (events != engine->flags &&
++	    utrace_set_events(tracee, engine, events))
++		return -ESRCH;
++
++	return action;
++}
++
++static int ptrace_resume(struct task_struct *tracee,
++				struct utrace_engine *engine,
++				long request, long data)
++{
++	struct ptrace_context *ctx = ptrace_context(engine);
++	int action;
++
++	if (!valid_signal(data))
++		return -EIO;
++
++	action = ptrace_resume_action(tracee, engine, request);
++	if (action < 0)
++		return action;
++
++	switch (get_stop_event(ctx)) {
++	case PTRACE_EVENT_VFORK:
++		if (ctx->options & PTRACE_O_TRACEVFORKDONE) {
++			set_stop_code(ctx, PTRACE_EVENT_VFORK_DONE);
++			action = UTRACE_REPORT;
++		}
++		break;
++
++	case PTRACE_EVENT_EXEC:
++	case PTRACE_EVENT_FORK:
++	case PTRACE_EVENT_CLONE:
++	case PTRACE_EVENT_VFORK_DONE:
++		if (request == PTRACE_SYSCALL) {
++			set_syscall_code(ctx);
++			do_ptrace_notify_stop(ctx, tracee);
++			return 0;
++		}
++
++		if (action != UTRACE_RESUME) {
++			/*
++			 * single-stepping. UTRACE_SIGNAL_REPORT will
++			 * synthesize a trap to follow the syscall insn.
++			*/
++			ctx->signr = SIGTRAP;
++			action = UTRACE_INTERRUPT;
++		}
++		break;
++
++	case PTRACE_EVENT_SYSCALL:
++		if (data)
++			send_sig_info(data, SEND_SIG_PRIV, tracee);
++		break;
++
++	case PTRACE_EVENT_SIGNAL:
++		ctx->signr = data;
++		break;
++	}
++
++	ctx->resume = action;
++	ptrace_wake_up(tracee, engine, action, true);
++	return 0;
++}
++
++extern int ptrace_regset(struct task_struct *task, int req, unsigned int type,
++			 struct iovec *kiov);
++
++int ptrace_request(struct task_struct *child, long request,
++		   long addr, long data)
++{
++	struct utrace_engine *engine = ptrace_lookup_engine(child);
++	siginfo_t siginfo;
++	int ret;
++
++	if (unlikely(IS_ERR(engine)))
++		return -ESRCH;
++
++	switch (request) {
++	case PTRACE_PEEKTEXT:
++	case PTRACE_PEEKDATA:
++		ret = generic_ptrace_peekdata(child, addr, data);
++		break;
++	case PTRACE_POKETEXT:
++	case PTRACE_POKEDATA:
++		ret = generic_ptrace_pokedata(child, addr, data);
++		break;
++
++#ifdef PTRACE_OLDSETOPTIONS
++	case PTRACE_OLDSETOPTIONS:
++#endif
++	case PTRACE_SETOPTIONS:
++		ret = ptrace_set_options(child, engine, data);
++		break;
++	case PTRACE_GETEVENTMSG:
++		ret = put_user(ptrace_context(engine)->eventmsg,
++				(unsigned long __user *) data);
++		break;
++
++	case PTRACE_GETSIGINFO:
++		ret = ptrace_rw_siginfo(child, ptrace_context(engine),
++					&siginfo, false);
++		if (!ret)
++			ret = copy_siginfo_to_user((siginfo_t __user *) data,
++						   &siginfo);
++		break;
++
++	case PTRACE_SETSIGINFO:
++		if (copy_from_user(&siginfo, (siginfo_t __user *) data,
++				   sizeof siginfo))
++			ret = -EFAULT;
++		else
++			ret = ptrace_rw_siginfo(child, ptrace_context(engine),
++						&siginfo, true);
++		break;
++
++	case PTRACE_DETACH:	 /* detach a process that was attached. */
++		ret = ptrace_detach(child, data);
++		break;
++
++	case PTRACE_KILL:
++		/* Ugly historical behaviour. */
++		if (task_is_traced(child))
++			ptrace_resume(child, engine, PTRACE_CONT, SIGKILL);
++		ret = 0;
++		break;
++
++	case PTRACE_GETREGSET:
++	case PTRACE_SETREGSET:
++	{
++		struct iovec kiov;
++		struct iovec __user *uiov = (struct iovec __user *) data;
++
++		if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
++			return -EFAULT;
++
++		if (__get_user(kiov.iov_base, &uiov->iov_base) ||
++		    __get_user(kiov.iov_len, &uiov->iov_len))
++			return -EFAULT;
++
++		ret = ptrace_regset(child, request, addr, &kiov);
++		if (!ret)
++			ret = __put_user(kiov.iov_len, &uiov->iov_len);
++		break;
++	}
++
++	default:
++		ret = ptrace_resume(child, engine, request, data);
++		break;
++	}
++
++	utrace_engine_put(engine);
++	return ret;
++}
++
++#if defined CONFIG_COMPAT
++#include <linux/compat.h>
++
++int compat_ptrace_request(struct task_struct *child, compat_long_t request,
++			  compat_ulong_t addr, compat_ulong_t data)
++{
++	struct utrace_engine *engine = ptrace_lookup_engine(child);
++	compat_ulong_t __user *datap = compat_ptr(data);
++	compat_ulong_t word;
++	siginfo_t siginfo;
++	int ret;
++
++	if (unlikely(IS_ERR(engine)))
++		return -ESRCH;
++
++	switch (request) {
++	case PTRACE_PEEKTEXT:
++	case PTRACE_PEEKDATA:
++		ret = access_process_vm(child, addr, &word, sizeof(word), 0);
++		if (ret != sizeof(word))
++			ret = -EIO;
++		else
++			ret = put_user(word, datap);
++		break;
++
++	case PTRACE_POKETEXT:
++	case PTRACE_POKEDATA:
++		ret = access_process_vm(child, addr, &data, sizeof(data), 1);
++		ret = (ret != sizeof(data) ? -EIO : 0);
++		break;
++
++	case PTRACE_GETEVENTMSG:
++		ret = put_user((compat_ulong_t)ptrace_context(engine)->eventmsg,
++				datap);
++		break;
++
++	case PTRACE_GETSIGINFO:
++		ret = ptrace_rw_siginfo(child, ptrace_context(engine),
++					&siginfo, false);
++		if (!ret)
++			ret = copy_siginfo_to_user32(
++				(struct compat_siginfo __user *) datap,
++				&siginfo);
++		break;
++
++	case PTRACE_SETSIGINFO:
++		memset(&siginfo, 0, sizeof siginfo);
++		if (copy_siginfo_from_user32(
++			    &siginfo, (struct compat_siginfo __user *) datap))
++			ret = -EFAULT;
++		else
++			ret = ptrace_rw_siginfo(child, ptrace_context(engine),
++						&siginfo, true);
++		break;
++
++	case PTRACE_GETREGSET:
++	case PTRACE_SETREGSET:
++	{
++		struct iovec kiov;
++		struct compat_iovec __user *uiov =
++			(struct compat_iovec __user *) datap;
++		compat_uptr_t ptr;
++		compat_size_t len;
++
++		if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
++			return -EFAULT;
++
++		if (__get_user(ptr, &uiov->iov_base) ||
++		    __get_user(len, &uiov->iov_len))
++			return -EFAULT;
++
++		kiov.iov_base = compat_ptr(ptr);
++		kiov.iov_len = len;
++
++		ret = ptrace_regset(child, request, addr, &kiov);
++		if (!ret)
++			ret = __put_user(kiov.iov_len, &uiov->iov_len);
++		break;
++	}
++
++	default:
++		ret = ptrace_request(child, request, addr, data);
++	}
++
++	utrace_engine_put(engine);
++	return ret;
++}
++#endif	/* CONFIG_COMPAT */
+diff --git a/kernel/ptrace.c b/kernel/ptrace.c
+index 23bde94..daed9e8 100644  
+--- a/kernel/ptrace.c
++++ b/kernel/ptrace.c
+@@ -15,7 +15,6 @@
+ #include <linux/highmem.h>
+ #include <linux/pagemap.h>
+ #include <linux/ptrace.h>
+-#include <linux/utrace.h>
+ #include <linux/security.h>
+ #include <linux/signal.h>
+ #include <linux/audit.h>
+@@ -24,7 +23,317 @@
+ #include <linux/uaccess.h>
+ #include <linux/regset.h>
+ 
++int __ptrace_may_access(struct task_struct *task, unsigned int mode)
++{
++	const struct cred *cred = current_cred(), *tcred;
++
++	/* May we inspect the given task?
++	 * This check is used both for attaching with ptrace
++	 * and for allowing access to sensitive information in /proc.
++	 *
++	 * ptrace_attach denies several cases that /proc allows
++	 * because setting up the necessary parent/child relationship
++	 * or halting the specified task is impossible.
++	 */
++	int dumpable = 0;
++	/* Don't let security modules deny introspection */
++	if (task == current)
++		return 0;
++	rcu_read_lock();
++	tcred = __task_cred(task);
++	if ((cred->uid != tcred->euid ||
++	     cred->uid != tcred->suid ||
++	     cred->uid != tcred->uid  ||
++	     cred->gid != tcred->egid ||
++	     cred->gid != tcred->sgid ||
++	     cred->gid != tcred->gid) &&
++	    !capable(CAP_SYS_PTRACE)) {
++		rcu_read_unlock();
++		return -EPERM;
++	}
++	rcu_read_unlock();
++	smp_rmb();
++	if (task->mm)
++		dumpable = get_dumpable(task->mm);
++	if (!dumpable && !capable(CAP_SYS_PTRACE))
++		return -EPERM;
++
++	return security_ptrace_access_check(task, mode);
++}
++
++bool ptrace_may_access(struct task_struct *task, unsigned int mode)
++{
++	int err;
++	task_lock(task);
++	err = __ptrace_may_access(task, mode);
++	task_unlock(task);
++	return !err;
++}
++
++/*
++ * Called with irqs disabled, returns true if childs should reap themselves.
++ */
++static int ignoring_children(struct sighand_struct *sigh)
++{
++	int ret;
++	spin_lock(&sigh->siglock);
++	ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
++	      (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
++	spin_unlock(&sigh->siglock);
++	return ret;
++}
++
++/*
++ * Called with tasklist_lock held for writing.
++ * Unlink a traced task, and clean it up if it was a traced zombie.
++ * Return true if it needs to be reaped with release_task().
++ * (We can't call release_task() here because we already hold tasklist_lock.)
++ *
++ * If it's a zombie, our attachedness prevented normal parent notification
++ * or self-reaping.  Do notification now if it would have happened earlier.
++ * If it should reap itself, return true.
++ *
++ * If it's our own child, there is no notification to do. But if our normal
++ * children self-reap, then this child was prevented by ptrace and we must
++ * reap it now, in that case we must also wake up sub-threads sleeping in
++ * do_wait().
++ */
++bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
++{
++	__ptrace_unlink(p);
++
++	if (p->exit_state == EXIT_ZOMBIE) {
++		if (!task_detached(p) && thread_group_empty(p)) {
++			if (!same_thread_group(p->real_parent, tracer))
++				do_notify_parent(p, p->exit_signal);
++			else if (ignoring_children(tracer->sighand)) {
++				__wake_up_parent(p, tracer);
++				p->exit_signal = -1;
++			}
++		}
++		if (task_detached(p)) {
++			/* Mark it as in the process of being reaped. */
++			p->exit_state = EXIT_DEAD;
++			return true;
++		}
++	}
++
++	return false;
++}
++
++int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
++{
++	int copied = 0;
++
++	while (len > 0) {
++		char buf[128];
++		int this_len, retval;
++
++		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
++		retval = access_process_vm(tsk, src, buf, this_len, 0);
++		if (!retval) {
++			if (copied)
++				break;
++			return -EIO;
++		}
++		if (copy_to_user(dst, buf, retval))
++			return -EFAULT;
++		copied += retval;
++		src += retval;
++		dst += retval;
++		len -= retval;
++	}
++	return copied;
++}
++
++int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
++{
++	int copied = 0;
++
++	while (len > 0) {
++		char buf[128];
++		int this_len, retval;
++
++		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
++		if (copy_from_user(buf, src, this_len))
++			return -EFAULT;
++		retval = access_process_vm(tsk, dst, buf, this_len, 1);
++		if (!retval) {
++			if (copied)
++				break;
++			return -EIO;
++		}
++		copied += retval;
++		src += retval;
++		dst += retval;
++		len -= retval;
++	}
++	return copied;
++}
++
++#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
++
++static const struct user_regset *
++find_regset(const struct user_regset_view *view, unsigned int type)
++{
++	const struct user_regset *regset;
++	int n;
++
++	for (n = 0; n < view->n; ++n) {
++		regset = view->regsets + n;
++		if (regset->core_note_type == type)
++			return regset;
++	}
++
++	return NULL;
++}
++
++int ptrace_regset(struct task_struct *task, int req, unsigned int type,
++		  struct iovec *kiov)
++{
++	const struct user_regset_view *view = task_user_regset_view(task);
++	const struct user_regset *regset = find_regset(view, type);
++	int regset_no;
++
++	if (!regset || (kiov->iov_len % regset->size) != 0)
++		return -EINVAL;
++
++	regset_no = regset - view->regsets;
++	kiov->iov_len = min(kiov->iov_len,
++			    (__kernel_size_t) (regset->n * regset->size));
++
++	if (req == PTRACE_GETREGSET)
++		return copy_regset_to_user(task, view, regset_no, 0,
++					   kiov->iov_len, kiov->iov_base);
++	else
++		return copy_regset_from_user(task, view, regset_no, 0,
++					     kiov->iov_len, kiov->iov_base);
++}
++
++#endif
++
++static struct task_struct *ptrace_get_task_struct(pid_t pid)
++{
++	struct task_struct *child;
++
++	rcu_read_lock();
++	child = find_task_by_vpid(pid);
++	if (child)
++		get_task_struct(child);
++	rcu_read_unlock();
++
++	if (!child)
++		return ERR_PTR(-ESRCH);
++	return child;
++}
++
++#ifndef arch_ptrace_attach
++#define arch_ptrace_attach(child)	do { } while (0)
++#endif
++
++SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
++{
++	struct task_struct *child;
++	long ret;
++
++	if (request == PTRACE_TRACEME) {
++		ret = ptrace_traceme();
++		if (!ret)
++			arch_ptrace_attach(current);
++		goto out;
++	}
++
++	child = ptrace_get_task_struct(pid);
++	if (IS_ERR(child)) {
++		ret = PTR_ERR(child);
++		goto out;
++	}
+ 
++	if (request == PTRACE_ATTACH) {
++		ret = ptrace_attach(child);
++		/*
++		 * Some architectures need to do book-keeping after
++		 * a ptrace attach.
++		 */
++		if (!ret)
++			arch_ptrace_attach(child);
++		goto out_put_task_struct;
++	}
++
++	ret = ptrace_check_attach(child, request == PTRACE_KILL);
++	if (ret < 0)
++		goto out_put_task_struct;
++
++	ret = arch_ptrace(child, request, addr, data);
++
++ out_put_task_struct:
++	put_task_struct(child);
++ out:
++	return ret;
++}
++
++int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
++{
++	unsigned long tmp;
++	int copied;
++
++	copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
++	if (copied != sizeof(tmp))
++		return -EIO;
++	return put_user(tmp, (unsigned long __user *)data);
++}
++
++int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
++{
++	int copied;
++
++	copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
++	return (copied == sizeof(data)) ? 0 : -EIO;
++}
++
++#if defined CONFIG_COMPAT
++#include <linux/compat.h>
++
++asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
++				  compat_long_t addr, compat_long_t data)
++{
++	struct task_struct *child;
++	long ret;
++
++	if (request == PTRACE_TRACEME) {
++		ret = ptrace_traceme();
++		goto out;
++	}
++
++	child = ptrace_get_task_struct(pid);
++	if (IS_ERR(child)) {
++		ret = PTR_ERR(child);
++		goto out;
++	}
++
++	if (request == PTRACE_ATTACH) {
++		ret = ptrace_attach(child);
++		/*
++		 * Some architectures need to do book-keeping after
++		 * a ptrace attach.
++		 */
++		if (!ret)
++			arch_ptrace_attach(child);
++		goto out_put_task_struct;
++	}
++
++	ret = ptrace_check_attach(child, request == PTRACE_KILL);
++	if (!ret)
++		ret = compat_arch_ptrace(child, request, addr, data);
++
++ out_put_task_struct:
++	put_task_struct(child);
++ out:
++	return ret;
++}
++#endif	/* CONFIG_COMPAT */
++
++#ifndef CONFIG_UTRACE
+ /*
+  * ptrace a task: make the debugger its new parent and
+  * move it to the ptrace list.
+@@ -117,61 +426,6 @@ int ptrace_check_attach(struct task_stru
+ 	return ret;
+ }
+ 
+-int __ptrace_may_access(struct task_struct *task, unsigned int mode)
+-{
+-	const struct cred *cred = current_cred(), *tcred;
+-
+-	/* May we inspect the given task?
+-	 * This check is used both for attaching with ptrace
+-	 * and for allowing access to sensitive information in /proc.
+-	 *
+-	 * ptrace_attach denies several cases that /proc allows
+-	 * because setting up the necessary parent/child relationship
+-	 * or halting the specified task is impossible.
+-	 */
+-	int dumpable = 0;
+-	/* Don't let security modules deny introspection */
+-	if (task == current)
+-		return 0;
+-	rcu_read_lock();
+-	tcred = __task_cred(task);
+-	if ((cred->uid != tcred->euid ||
+-	     cred->uid != tcred->suid ||
+-	     cred->uid != tcred->uid  ||
+-	     cred->gid != tcred->egid ||
+-	     cred->gid != tcred->sgid ||
+-	     cred->gid != tcred->gid) &&
+-	    !capable(CAP_SYS_PTRACE)) {
+-		rcu_read_unlock();
+-		return -EPERM;
+-	}
+-	rcu_read_unlock();
+-	smp_rmb();
+-	if (task->mm)
+-		dumpable = get_dumpable(task->mm);
+-	if (!dumpable && !capable(CAP_SYS_PTRACE))
+-		return -EPERM;
+-
+-	return security_ptrace_access_check(task, mode);
+-}
+-
+-bool ptrace_may_access(struct task_struct *task, unsigned int mode)
+-{
+-	int err;
+-	task_lock(task);
+-	err = __ptrace_may_access(task, mode);
+-	task_unlock(task);
+-	return !err;
+-}
+-
+-/*
+- * For experimental use of utrace, exclude ptrace on the same task.
+- */
+-static inline bool exclude_ptrace(struct task_struct *task)
+-{
+-	return unlikely(!!task_utrace_flags(task));
+-}
+-
+ int ptrace_attach(struct task_struct *task)
+ {
+ 	int retval;
+@@ -195,8 +449,6 @@ int ptrace_attach(struct task_struct *ta
+ 
+ 	task_lock(task);
+ 	retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
+-	if (!retval && exclude_ptrace(task))
+-		retval = -EBUSY;
+ 	task_unlock(task);
+ 	if (retval)
+ 		goto unlock_creds;
+@@ -217,94 +469,40 @@ int ptrace_attach(struct task_struct *ta
+ 
+ 	retval = 0;
+ unlock_tasklist:
+-	write_unlock_irq(&tasklist_lock);
+-unlock_creds:
+-	mutex_unlock(&task->cred_guard_mutex);
+-out:
+-	return retval;
+-}
+-
+-/**
+- * ptrace_traceme  --  helper for PTRACE_TRACEME
+- *
+- * Performs checks and sets PT_PTRACED.
+- * Should be used by all ptrace implementations for PTRACE_TRACEME.
+- */
+-int ptrace_traceme(void)
+-{
+-	int ret = -EPERM;
+-
+-	if (exclude_ptrace(current)) /* XXX locking */
+-		return -EBUSY;
+-
+-	write_lock_irq(&tasklist_lock);
+-	/* Are we already being traced? */
+-	if (!current->ptrace) {
+-		ret = security_ptrace_traceme(current->parent);
+-		/*
+-		 * Check PF_EXITING to ensure ->real_parent has not passed
+-		 * exit_ptrace(). Otherwise we don't report the error but
+-		 * pretend ->real_parent untraces us right after return.
+-		 */
+-		if (!ret && !(current->real_parent->flags & PF_EXITING)) {
+-			current->ptrace = PT_PTRACED;
+-			__ptrace_link(current, current->real_parent);
+-		}
+-	}
+-	write_unlock_irq(&tasklist_lock);
+-
+-	return ret;
+-}
+-
+-/*
+- * Called with irqs disabled, returns true if childs should reap themselves.
+- */
+-static int ignoring_children(struct sighand_struct *sigh)
+-{
+-	int ret;
+-	spin_lock(&sigh->siglock);
+-	ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
+-	      (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
+-	spin_unlock(&sigh->siglock);
+-	return ret;
+-}
+-
+-/*
+- * Called with tasklist_lock held for writing.
+- * Unlink a traced task, and clean it up if it was a traced zombie.
+- * Return true if it needs to be reaped with release_task().
+- * (We can't call release_task() here because we already hold tasklist_lock.)
+- *
+- * If it's a zombie, our attachedness prevented normal parent notification
+- * or self-reaping.  Do notification now if it would have happened earlier.
+- * If it should reap itself, return true.
++	write_unlock_irq(&tasklist_lock);
++unlock_creds:
++	mutex_unlock(&task->cred_guard_mutex);
++out:
++	return retval;
++}
++
++/**
++ * ptrace_traceme  --  helper for PTRACE_TRACEME
+  *
+- * If it's our own child, there is no notification to do. But if our normal
+- * children self-reap, then this child was prevented by ptrace and we must
+- * reap it now, in that case we must also wake up sub-threads sleeping in
+- * do_wait().
++ * Performs checks and sets PT_PTRACED.
++ * Should be used by all ptrace implementations for PTRACE_TRACEME.
+  */
+-bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
++int ptrace_traceme(void)
+ {
+-	__ptrace_unlink(p);
++	int ret = -EPERM;
+ 
+-	if (p->exit_state == EXIT_ZOMBIE) {
+-		if (!task_detached(p) && thread_group_empty(p)) {
+-			if (!same_thread_group(p->real_parent, tracer))
+-				do_notify_parent(p, p->exit_signal);
+-			else if (ignoring_children(tracer->sighand)) {
+-				__wake_up_parent(p, tracer);
+-				p->exit_signal = -1;
+-			}
+-		}
+-		if (task_detached(p)) {
+-			/* Mark it as in the process of being reaped. */
+-			p->exit_state = EXIT_DEAD;
+-			return true;
++	write_lock_irq(&tasklist_lock);
++	/* Are we already being traced? */
++	if (!current->ptrace) {
++		ret = security_ptrace_traceme(current->parent);
++		/*
++		 * Check PF_EXITING to ensure ->real_parent has not passed
++		 * exit_ptrace(). Otherwise we don't report the error but
++		 * pretend ->real_parent untraces us right after return.
++		 */
++		if (!ret && !(current->real_parent->flags & PF_EXITING)) {
++			current->ptrace = PT_PTRACED;
++			__ptrace_link(current, current->real_parent);
+ 		}
+ 	}
++	write_unlock_irq(&tasklist_lock);
+ 
+-	return false;
++	return ret;
+ }
+ 
+ int ptrace_detach(struct task_struct *child, unsigned int data)
+@@ -366,56 +564,6 @@ void exit_ptrace(struct task_struct *tra
+ 	write_lock_irq(&tasklist_lock);
+ }
+ 
+-int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
+-{
+-	int copied = 0;
+-
+-	while (len > 0) {
+-		char buf[128];
+-		int this_len, retval;
+-
+-		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+-		retval = access_process_vm(tsk, src, buf, this_len, 0);
+-		if (!retval) {
+-			if (copied)
+-				break;
+-			return -EIO;
+-		}
+-		if (copy_to_user(dst, buf, retval))
+-			return -EFAULT;
+-		copied += retval;
+-		src += retval;
+-		dst += retval;
+-		len -= retval;
+-	}
+-	return copied;
+-}
+-
+-int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
+-{
+-	int copied = 0;
+-
+-	while (len > 0) {
+-		char buf[128];
+-		int this_len, retval;
+-
+-		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+-		if (copy_from_user(buf, src, this_len))
+-			return -EFAULT;
+-		retval = access_process_vm(tsk, dst, buf, this_len, 1);
+-		if (!retval) {
+-			if (copied)
+-				break;
+-			return -EIO;
+-		}
+-		copied += retval;
+-		src += retval;
+-		dst += retval;
+-		len -= retval;
+-	}
+-	return copied;
+-}
+-
+ static int ptrace_setoptions(struct task_struct *child, long data)
+ {
+ 	child->ptrace &= ~PT_TRACE_MASK;
+@@ -530,47 +677,6 @@ static int ptrace_resume(struct task_str
+ 	return 0;
+ }
+ 
+-#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+-
+-static const struct user_regset *
+-find_regset(const struct user_regset_view *view, unsigned int type)
+-{
+-	const struct user_regset *regset;
+-	int n;
+-
+-	for (n = 0; n < view->n; ++n) {
+-		regset = view->regsets + n;
+-		if (regset->core_note_type == type)
+-			return regset;
+-	}
+-
+-	return NULL;
+-}
+-
+-static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
+-			 struct iovec *kiov)
+-{
+-	const struct user_regset_view *view = task_user_regset_view(task);
+-	const struct user_regset *regset = find_regset(view, type);
+-	int regset_no;
+-
+-	if (!regset || (kiov->iov_len % regset->size) != 0)
+-		return -EINVAL;
+-
+-	regset_no = regset - view->regsets;
+-	kiov->iov_len = min(kiov->iov_len,
+-			    (__kernel_size_t) (regset->n * regset->size));
+-
+-	if (req == PTRACE_GETREGSET)
+-		return copy_regset_to_user(task, view, regset_no, 0,
+-					   kiov->iov_len, kiov->iov_base);
+-	else
+-		return copy_regset_from_user(task, view, regset_no, 0,
+-					     kiov->iov_len, kiov->iov_base);
+-}
+-
+-#endif
+-
+ int ptrace_request(struct task_struct *child, long request,
+ 		   long addr, long data)
+ {
+@@ -686,88 +792,7 @@ int ptrace_request(struct task_struct *c
+ 	return ret;
+ }
+ 
+-static struct task_struct *ptrace_get_task_struct(pid_t pid)
+-{
+-	struct task_struct *child;
+-
+-	rcu_read_lock();
+-	child = find_task_by_vpid(pid);
+-	if (child)
+-		get_task_struct(child);
+-	rcu_read_unlock();
+-
+-	if (!child)
+-		return ERR_PTR(-ESRCH);
+-	return child;
+-}
+-
+-#ifndef arch_ptrace_attach
+-#define arch_ptrace_attach(child)	do { } while (0)
+-#endif
+-
+-SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
+-{
+-	struct task_struct *child;
+-	long ret;
+-
+-	if (request == PTRACE_TRACEME) {
+-		ret = ptrace_traceme();
+-		if (!ret)
+-			arch_ptrace_attach(current);
+-		goto out;
+-	}
+-
+-	child = ptrace_get_task_struct(pid);
+-	if (IS_ERR(child)) {
+-		ret = PTR_ERR(child);
+-		goto out;
+-	}
+-
+-	if (request == PTRACE_ATTACH) {
+-		ret = ptrace_attach(child);
+-		/*
+-		 * Some architectures need to do book-keeping after
+-		 * a ptrace attach.
+-		 */
+-		if (!ret)
+-			arch_ptrace_attach(child);
+-		goto out_put_task_struct;
+-	}
+-
+-	ret = ptrace_check_attach(child, request == PTRACE_KILL);
+-	if (ret < 0)
+-		goto out_put_task_struct;
+-
+-	ret = arch_ptrace(child, request, addr, data);
+-
+- out_put_task_struct:
+-	put_task_struct(child);
+- out:
+-	return ret;
+-}
+-
+-int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
+-{
+-	unsigned long tmp;
+-	int copied;
+-
+-	copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
+-	if (copied != sizeof(tmp))
+-		return -EIO;
+-	return put_user(tmp, (unsigned long __user *)data);
+-}
+-
+-int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
+-{
+-	int copied;
+-
+-	copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
+-	return (copied == sizeof(data)) ? 0 : -EIO;
+-}
+-
+ #if defined CONFIG_COMPAT
+-#include <linux/compat.h>
+-
+ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
+ 			  compat_ulong_t addr, compat_ulong_t data)
+ {
+@@ -845,42 +870,5 @@ int compat_ptrace_request(struct task_st
+ 
+ 	return ret;
+ }
+-
+-asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
+-				  compat_long_t addr, compat_long_t data)
+-{
+-	struct task_struct *child;
+-	long ret;
+-
+-	if (request == PTRACE_TRACEME) {
+-		ret = ptrace_traceme();
+-		goto out;
+-	}
+-
+-	child = ptrace_get_task_struct(pid);
+-	if (IS_ERR(child)) {
+-		ret = PTR_ERR(child);
+-		goto out;
+-	}
+-
+-	if (request == PTRACE_ATTACH) {
+-		ret = ptrace_attach(child);
+-		/*
+-		 * Some architectures need to do book-keeping after
+-		 * a ptrace attach.
+-		 */
+-		if (!ret)
+-			arch_ptrace_attach(child);
+-		goto out_put_task_struct;
+-	}
+-
+-	ret = ptrace_check_attach(child, request == PTRACE_KILL);
+-	if (!ret)
+-		ret = compat_arch_ptrace(child, request, addr, data);
+-
+- out_put_task_struct:
+-	put_task_struct(child);
+- out:
+-	return ret;
+-}
+ #endif	/* CONFIG_COMPAT */
++#endif	/* CONFIG_UTRACE */
+diff --git a/kernel/utrace.c b/kernel/utrace.c
+index 43f38b7..fd21b7b 100644  
+--- a/kernel/utrace.c
++++ b/kernel/utrace.c
+@@ -809,6 +809,22 @@ relock:
+ 	spin_unlock_irq(&task->sighand->siglock);
+ 	spin_unlock(&utrace->lock);
+ 
++	/*
++	 * If ptrace is among the reasons for this stop, do its
++	 * notification now.  This could not just be done in
++	 * ptrace's own event report callbacks because it has to
++	 * be done after we are in TASK_TRACED.  This makes the
++	 * synchronization with ptrace_do_wait() work right.
++	 *
++	 * It's only because of the bad old overloading of the do_wait()
++	 * logic for handling ptrace stops that we need this special case
++	 * here.  One day we will clean up ptrace so it does not need to
++	 * work this way.  New things that are designed sensibly don't need
++	 * a wakeup that synchronizes with tasklist_lock and ->state, so
++	 * the proper utrace API does not try to support this weirdness.
++	 */
++	ptrace_notify_stop(task);
++
+ 	schedule();
+ 
+ 	utrace_finish_stop();