Merge branch 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc

* 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc: (39 commits)
  ptrace: do_wait(traced_leader_killed_by_mt_exec) can block forever
  ptrace: fix ptrace_signal() && STOP_DEQUEUED interaction
  connector: add an event for monitoring process tracers
  ptrace: dont send SIGSTOP on auto-attach if PT_SEIZED
  ptrace: mv send-SIGSTOP from do_fork() to ptrace_init_task()
  ptrace_init_task: initialize child->jobctl explicitly
  has_stopped_jobs: s/task_is_stopped/SIGNAL_STOP_STOPPED/
  ptrace: make former thread ID available via PTRACE_GETEVENTMSG after PTRACE_EVENT_EXEC stop
  ptrace: wait_consider_task: s/same_thread_group/ptrace_reparented/
  ptrace: kill real_parent_is_ptracer() in in favor of ptrace_reparented()
  ptrace: ptrace_reparented() should check same_thread_group()
  redefine thread_group_leader() as exit_signal >= 0
  do not change dead_task->exit_signal
  kill task_detached()
  reparent_leader: check EXIT_DEAD instead of task_detached()
  make do_notify_parent() __must_check, update the callers
  __ptrace_detach: avoid task_detached(), check do_notify_parent()
  kill tracehook_notify_death()
  make do_notify_parent() return bool
  ptrace: s/tracehook_tracer_task()/ptrace_parent()/
  ...

arch/s390/kernel/traps.c

@@ -331,7 +331,7 @@ void __kprobes do_per_trap(struct pt_regs *regs)
 {
 	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
 		return;
-	if (tracehook_consider_fatal_signal(current, SIGTRAP))
+	if (current->ptrace)
 		force_sig(SIGTRAP, current);
 }
 
@@ -425,7 +425,7 @@ static void __kprobes illegal_op(struct pt_regs *regs, long pgm_int_code,
 		if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
 			return;
 		if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
-			if (tracehook_consider_fatal_signal(current, SIGTRAP))
+			if (current->ptrace)
 				force_sig(SIGTRAP, current);
 			else
 				signal = SIGILL;

drivers/connector/cn_proc.c

@@ -28,6 +28,7 @@
 #include <linux/init.h>
 #include <linux/connector.h>
 #include <linux/gfp.h>
+#include <linux/ptrace.h>
 #include <asm/atomic.h>
 #include <asm/unaligned.h>
 
@@ -166,6 +167,40 @@ void proc_sid_connector(struct task_struct *task)
 	cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 }
 
+void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
+{
+	struct cn_msg *msg;
+	struct proc_event *ev;
+	struct timespec ts;
+	__u8 buffer[CN_PROC_MSG_SIZE];
+	struct task_struct *tracer;
+
+	if (atomic_read(&proc_event_num_listeners) < 1)
+		return;
+
+	msg = (struct cn_msg *)buffer;
+	ev = (struct proc_event *)msg->data;
+	get_seq(&msg->seq, &ev->cpu);
+	ktime_get_ts(&ts); /* get high res monotonic timestamp */
+	put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
+	ev->what = PROC_EVENT_PTRACE;
+	ev->event_data.ptrace.process_pid  = task->pid;
+	ev->event_data.ptrace.process_tgid = task->tgid;
+	if (ptrace_id == PTRACE_ATTACH) {
+		ev->event_data.ptrace.tracer_pid  = current->pid;
+		ev->event_data.ptrace.tracer_tgid = current->tgid;
+	} else if (ptrace_id == PTRACE_DETACH) {
+		ev->event_data.ptrace.tracer_pid  = 0;
+		ev->event_data.ptrace.tracer_tgid = 0;
+	} else
+		return;
+
+	memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+	msg->ack = 0; /* not used */
+	msg->len = sizeof(*ev);
+	cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
+}
+
 void proc_exit_connector(struct task_struct *task)
 {
 	struct cn_msg *msg;

fs/exec.c

@@ -963,9 +963,18 @@ static int de_thread(struct task_struct *tsk)
 		leader->group_leader = tsk;
 
 		tsk->exit_signal = SIGCHLD;
+		leader->exit_signal = -1;
 
 		BUG_ON(leader->exit_state != EXIT_ZOMBIE);
 		leader->exit_state = EXIT_DEAD;
+
+		/*
+		 * We are going to release_task()->ptrace_unlink() silently,
+		 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees
+		 * the tracer wont't block again waiting for this thread.
+		 */
+		if (unlikely(leader->ptrace))
+			__wake_up_parent(leader, leader->parent);
 		write_unlock_irq(&tasklist_lock);
 
 		release_task(leader);
@@ -1225,7 +1234,12 @@ int check_unsafe_exec(struct linux_binprm *bprm)
 	unsigned n_fs;
 	int res = 0;
 
-	bprm->unsafe = tracehook_unsafe_exec(p);
+	if (p->ptrace) {
+		if (p->ptrace & PT_PTRACE_CAP)
+			bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP;
+		else
+			bprm->unsafe |= LSM_UNSAFE_PTRACE;
+	}
 
 	n_fs = 1;
 	spin_lock(&p->fs->lock);
@@ -1353,6 +1367,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
 	unsigned int depth = bprm->recursion_depth;
 	int try,retval;
 	struct linux_binfmt *fmt;
+	pid_t old_pid;
 
 	retval = security_bprm_check(bprm);
 	if (retval)
@@ -1362,6 +1377,11 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
 	if (retval)
 		return retval;
 
+	/* Need to fetch pid before load_binary changes it */
+	rcu_read_lock();
+	old_pid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
+	rcu_read_unlock();
+
 	retval = -ENOENT;
 	for (try=0; try<2; try++) {
 		read_lock(&binfmt_lock);
@@ -1381,7 +1401,8 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
 			bprm->recursion_depth = depth;
 			if (retval >= 0) {
 				if (depth == 0)
-					tracehook_report_exec(fmt, bprm, regs);
+					ptrace_event(PTRACE_EVENT_EXEC,
+							old_pid);
 				put_binfmt(fmt);
 				allow_write_access(bprm->file);
 				if (bprm->file)
@@ -1769,7 +1790,7 @@ static int zap_process(struct task_struct *start, int exit_code)
 
 	t = start;
 	do {
-		task_clear_group_stop_pending(t);
+		task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
 		if (t != current && t->mm) {
 			sigaddset(&t->pending.signal, SIGKILL);
 			signal_wake_up(t, 1);

fs/proc/array.c

@@ -172,7 +172,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
 		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
 	tpid = 0;
 	if (pid_alive(p)) {
-		struct task_struct *tracer = tracehook_tracer_task(p);
+		struct task_struct *tracer = ptrace_parent(p);
 		if (tracer)
 			tpid = task_pid_nr_ns(tracer, ns);
 	}

fs/proc/base.c

@@ -216,7 +216,7 @@ static struct mm_struct *__check_mem_permission(struct task_struct *task)
 	if (task_is_stopped_or_traced(task)) {
 		int match;
 		rcu_read_lock();
-		match = (tracehook_tracer_task(task) == current);
+		match = (ptrace_parent(task) == current);
 		rcu_read_unlock();
 		if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
 			return mm;

include/linux/cn_proc.h

@@ -53,6 +53,7 @@ struct proc_event {
 		PROC_EVENT_UID  = 0x00000004,
 		PROC_EVENT_GID  = 0x00000040,
 		PROC_EVENT_SID  = 0x00000080,
+		PROC_EVENT_PTRACE = 0x00000100,
 		/* "next" should be 0x00000400 */
 		/* "last" is the last process event: exit */
 		PROC_EVENT_EXIT = 0x80000000
@@ -95,6 +96,13 @@ struct proc_event {
 			__kernel_pid_t process_tgid;
 		} sid;
 
+		struct ptrace_proc_event {
+			__kernel_pid_t process_pid;
+			__kernel_pid_t process_tgid;
+			__kernel_pid_t tracer_pid;
+			__kernel_pid_t tracer_tgid;
+		} ptrace;
+
 		struct exit_proc_event {
 			__kernel_pid_t process_pid;
 			__kernel_pid_t process_tgid;
@@ -109,6 +117,7 @@ void proc_fork_connector(struct task_struct *task);
 void proc_exec_connector(struct task_struct *task);
 void proc_id_connector(struct task_struct *task, int which_id);
 void proc_sid_connector(struct task_struct *task);
+void proc_ptrace_connector(struct task_struct *task, int which_id);
 void proc_exit_connector(struct task_struct *task);
 #else
 static inline void proc_fork_connector(struct task_struct *task)
@@ -124,6 +133,10 @@ static inline void proc_id_connector(struct task_struct *task,
 static inline void proc_sid_connector(struct task_struct *task)
 {}
 
+static inline void proc_ptrace_connector(struct task_struct *task,
+					 int ptrace_id)
+{}
+
 static inline void proc_exit_connector(struct task_struct *task)
 {}
 #endif	/* CONFIG_PROC_EVENTS */

include/linux/ptrace.h

@@ -47,6 +47,13 @@
 #define PTRACE_GETREGSET	0x4204
 #define PTRACE_SETREGSET	0x4205
 
+#define PTRACE_SEIZE		0x4206
+#define PTRACE_INTERRUPT	0x4207
+#define PTRACE_LISTEN		0x4208
+
+/* flags in @data for PTRACE_SEIZE */
+#define PTRACE_SEIZE_DEVEL	0x80000000 /* temp flag for development */
+
 /* options set using PTRACE_SETOPTIONS */
 #define PTRACE_O_TRACESYSGOOD	0x00000001
 #define PTRACE_O_TRACEFORK	0x00000002
@@ -65,6 +72,7 @@
 #define PTRACE_EVENT_EXEC	4
 #define PTRACE_EVENT_VFORK_DONE	5
 #define PTRACE_EVENT_EXIT	6
+#define PTRACE_EVENT_STOP	7
 
 #include <asm/ptrace.h>
 
@@ -77,16 +85,22 @@
  * flags.  When the a task is stopped the ptracer owns task->ptrace.
  */
 
+#define PT_SEIZED	0x00010000	/* SEIZE used, enable new behavior */
 #define PT_PTRACED	0x00000001
 #define PT_DTRACE	0x00000002	/* delayed trace (used on m68k, i386) */
 #define PT_TRACESYSGOOD	0x00000004
 #define PT_PTRACE_CAP	0x00000008	/* ptracer can follow suid-exec */
-#define PT_TRACE_FORK	0x00000010
-#define PT_TRACE_VFORK	0x00000020
-#define PT_TRACE_CLONE	0x00000040
-#define PT_TRACE_EXEC	0x00000080
-#define PT_TRACE_VFORK_DONE	0x00000100
-#define PT_TRACE_EXIT	0x00000200
+
+/* PT_TRACE_* event enable flags */
+#define PT_EVENT_FLAG_SHIFT	4
+#define PT_EVENT_FLAG(event)	(1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))
+
+#define PT_TRACE_FORK		PT_EVENT_FLAG(PTRACE_EVENT_FORK)
+#define PT_TRACE_VFORK		PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
+#define PT_TRACE_CLONE		PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
+#define PT_TRACE_EXEC		PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
+#define PT_TRACE_VFORK_DONE	PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
+#define PT_TRACE_EXIT		PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
 
 #define PT_TRACE_MASK	0x000003f4
 
@@ -105,7 +119,7 @@ extern long arch_ptrace(struct task_struct *child, long request,
 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 extern void ptrace_disable(struct task_struct *);
-extern int ptrace_check_attach(struct task_struct *task, int kill);
+extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 extern int ptrace_request(struct task_struct *child, long request,
 			  unsigned long addr, unsigned long data);
 extern void ptrace_notify(int exit_code);
@@ -122,7 +136,7 @@ extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 
 static inline int ptrace_reparented(struct task_struct *child)
 {
-	return child->real_parent != child->parent;
+	return !same_thread_group(child->real_parent, child->parent);
 }
 
 static inline void ptrace_unlink(struct task_struct *child)
@@ -137,36 +151,56 @@ int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 			    unsigned long data);
 
 /**
- * task_ptrace - return %PT_* flags that apply to a task
- * @task:	pointer to &task_struct in question
+ * ptrace_parent - return the task that is tracing the given task
+ * @task: task to consider
  *
- * Returns the %PT_* flags that apply to @task.
+ * Returns %NULL if no one is tracing @task, or the &struct task_struct
+ * pointer to its tracer.
+ *
+ * Must called under rcu_read_lock().  The pointer returned might be kept
+ * live only by RCU.  During exec, this may be called with task_lock() held
+ * on @task, still held from when check_unsafe_exec() was called.
  */
-static inline int task_ptrace(struct task_struct *task)
+static inline struct task_struct *ptrace_parent(struct task_struct *task)
 {
-	return task->ptrace;
+	if (unlikely(task->ptrace))
+		return rcu_dereference(task->parent);
+	return NULL;
+}
+
+/**
+ * ptrace_event_enabled - test whether a ptrace event is enabled
+ * @task: ptracee of interest
+ * @event: %PTRACE_EVENT_* to test
+ *
+ * Test whether @event is enabled for ptracee @task.
+ *
+ * Returns %true if @event is enabled, %false otherwise.
+ */
+static inline bool ptrace_event_enabled(struct task_struct *task, int event)
+{
+	return task->ptrace & PT_EVENT_FLAG(event);
 }
 
 /**
  * ptrace_event - possibly stop for a ptrace event notification
- * @mask:	%PT_* bit to check in @current->ptrace
- * @event:	%PTRACE_EVENT_* value to report if @mask is set
+ * @event:	%PTRACE_EVENT_* value to report
  * @message:	value for %PTRACE_GETEVENTMSG to return
  *
- * This checks the @mask bit to see if ptrace wants stops for this event.
- * If so we stop, reporting @event and @message to the ptrace parent.
- *
- * Returns nonzero if we did a ptrace notification, zero if not.
+ * Check whether @event is enabled and, if so, report @event and @message
+ * to the ptrace parent.
  *
  * Called without locks.
  */
-static inline int ptrace_event(int mask, int event, unsigned long message)
+static inline void ptrace_event(int event, unsigned long message)
 {
-	if (mask && likely(!(current->ptrace & mask)))
-		return 0;
-	current->ptrace_message = message;
-	ptrace_notify((event << 8) | SIGTRAP);
-	return 1;
+	if (unlikely(ptrace_event_enabled(current, event))) {
+		current->ptrace_message = message;
+		ptrace_notify((event << 8) | SIGTRAP);
+	} else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
+		/* legacy EXEC report via SIGTRAP */
+		send_sig(SIGTRAP, current, 0);
+	}
 }
 
 /**
@@ -183,16 +217,24 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 {
 	INIT_LIST_HEAD(&child->ptrace_entry);
 	INIT_LIST_HEAD(&child->ptraced);
-	child->parent = child->real_parent;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	atomic_set(&child->ptrace_bp_refcnt, 1);
+#endif
+	child->jobctl = 0;
 	child->ptrace = 0;
-	if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
+	child->parent = child->real_parent;
+
+	if (unlikely(ptrace) && current->ptrace) {
 		child->ptrace = current->ptrace;
 		__ptrace_link(child, current->parent);
-	}
 
-#ifdef CONFIG_HAVE_HW_BREAKPOINT
-	atomic_set(&child->ptrace_bp_refcnt, 1);
-#endif
+		if (child->ptrace & PT_SEIZED)
+			task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
+		else
+			sigaddset(&child->pending.signal, SIGSTOP);
+
+		set_tsk_thread_flag(child, TIF_SIGPENDING);
+	}
 }
 
 /**

include/linux/sched.h

@@ -1292,7 +1292,7 @@ struct task_struct {
 	int exit_state;
 	int exit_code, exit_signal;
 	int pdeath_signal;  /*  The signal sent when the parent dies  */
-	unsigned int group_stop;	/* GROUP_STOP_*, siglock protected */
+	unsigned int jobctl;	/* JOBCTL_*, siglock protected */
 	/* ??? */
 	unsigned int personality;
 	unsigned did_exec:1;
@@ -1813,15 +1813,34 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
 #define used_math() tsk_used_math(current)
 
 /*
- * task->group_stop flags
+ * task->jobctl flags
  */
-#define GROUP_STOP_SIGMASK	0xffff    /* signr of the last group stop */
-#define GROUP_STOP_PENDING	(1 << 16) /* task should stop for group stop */
-#define GROUP_STOP_CONSUME	(1 << 17) /* consume group stop count */
-#define GROUP_STOP_TRAPPING	(1 << 18) /* switching from STOPPED to TRACED */
-#define GROUP_STOP_DEQUEUED	(1 << 19) /* stop signal dequeued */
-
-extern void task_clear_group_stop_pending(struct task_struct *task);
+#define JOBCTL_STOP_SIGMASK	0xffff	/* signr of the last group stop */
+
+#define JOBCTL_STOP_DEQUEUED_BIT 16	/* stop signal dequeued */
+#define JOBCTL_STOP_PENDING_BIT	17	/* task should stop for group stop */
+#define JOBCTL_STOP_CONSUME_BIT	18	/* consume group stop count */
+#define JOBCTL_TRAP_STOP_BIT	19	/* trap for STOP */
+#define JOBCTL_TRAP_NOTIFY_BIT	20	/* trap for NOTIFY */
+#define JOBCTL_TRAPPING_BIT	21	/* switching to TRACED */
+#define JOBCTL_LISTENING_BIT	22	/* ptracer is listening for events */
+
+#define JOBCTL_STOP_DEQUEUED	(1 << JOBCTL_STOP_DEQUEUED_BIT)
+#define JOBCTL_STOP_PENDING	(1 << JOBCTL_STOP_PENDING_BIT)
+#define JOBCTL_STOP_CONSUME	(1 << JOBCTL_STOP_CONSUME_BIT)
+#define JOBCTL_TRAP_STOP	(1 << JOBCTL_TRAP_STOP_BIT)
+#define JOBCTL_TRAP_NOTIFY	(1 << JOBCTL_TRAP_NOTIFY_BIT)
+#define JOBCTL_TRAPPING		(1 << JOBCTL_TRAPPING_BIT)
+#define JOBCTL_LISTENING	(1 << JOBCTL_LISTENING_BIT)
+
+#define JOBCTL_TRAP_MASK	(JOBCTL_TRAP_STOP | JOBCTL_TRAP_NOTIFY)
+#define JOBCTL_PENDING_MASK	(JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK)
+
+extern bool task_set_jobctl_pending(struct task_struct *task,
+				    unsigned int mask);
+extern void task_clear_jobctl_trapping(struct task_struct *task);
+extern void task_clear_jobctl_pending(struct task_struct *task,
+				      unsigned int mask);
 
 #ifdef CONFIG_PREEMPT_RCU
 
@@ -2136,7 +2155,7 @@ static inline int dequeue_signal_lock(struct task_struct *tsk, sigset_t *mask, s
 	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
 
 	return ret;
-}	
+}
 
 extern void block_all_signals(int (*notifier)(void *priv), void *priv,
 			      sigset_t *mask);
@@ -2151,7 +2170,7 @@ extern int kill_pid_info_as_uid(int, struct siginfo *, struct pid *, uid_t, uid_
 extern int kill_pgrp(struct pid *pid, int sig, int priv);
 extern int kill_pid(struct pid *pid, int sig, int priv);
 extern int kill_proc_info(int, struct siginfo *, pid_t);
-extern int do_notify_parent(struct task_struct *, int);
+extern __must_check bool do_notify_parent(struct task_struct *, int);
 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
 extern void force_sig(int, struct task_struct *);
 extern int send_sig(int, struct task_struct *, int);
@@ -2275,8 +2294,10 @@ static inline int get_nr_threads(struct task_struct *tsk)
 	return tsk->signal->nr_threads;
 }
 
-/* de_thread depends on thread_group_leader not being a pid based check */
-#define thread_group_leader(p)	(p == p->group_leader)
+static inline bool thread_group_leader(struct task_struct *p)
+{
+	return p->exit_signal >= 0;
+}
 
 /* Do to the insanities of de_thread it is possible for a process
  * to have the pid of the thread group leader without actually being
@@ -2309,11 +2330,6 @@ static inline int thread_group_empty(struct task_struct *p)
 #define delay_group_leader(p) \
 		(thread_group_leader(p) && !thread_group_empty(p))
 
-static inline int task_detached(struct task_struct *p)
-{
-	return p->exit_signal == -1;
-}
-
 /*
  * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
  * subscriptions and synchronises with wait4().  Also used in procfs.  Also

kernel/exit.c

@@ -169,7 +169,6 @@ void release_task(struct task_struct * p)
 	struct task_struct *leader;
 	int zap_leader;
 repeat:
-	tracehook_prepare_release_task(p);
 	/* don't need to get the RCU readlock here - the process is dead and
 	 * can't be modifying its own credentials. But shut RCU-lockdep up */
 	rcu_read_lock();
@@ -179,7 +178,7 @@ void release_task(struct task_struct * p)
 	proc_flush_task(p);
 
 	write_lock_irq(&tasklist_lock);
-	tracehook_finish_release_task(p);
+	ptrace_release_task(p);
 	__exit_signal(p);
 
 	/*
@@ -190,22 +189,12 @@ void release_task(struct task_struct * p)
 	zap_leader = 0;
 	leader = p->group_leader;
 	if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
-		BUG_ON(task_detached(leader));
-		do_notify_parent(leader, leader->exit_signal);
 		/*
 		 * If we were the last child thread and the leader has
 		 * exited already, and the leader's parent ignores SIGCHLD,
 		 * then we are the one who should release the leader.
-		 *
-		 * do_notify_parent() will have marked it self-reaping in
-		 * that case.
-		 */
-		zap_leader = task_detached(leader);
-
-		/*
-		 * This maintains the invariant that release_task()
-		 * only runs on a task in EXIT_DEAD, just for sanity.
 		 */
+		zap_leader = do_notify_parent(leader, leader->exit_signal);
 		if (zap_leader)
 			leader->exit_state = EXIT_DEAD;
 	}
@@ -277,18 +266,16 @@ int is_current_pgrp_orphaned(void)
 	return retval;
 }
 
-static int has_stopped_jobs(struct pid *pgrp)
+static bool has_stopped_jobs(struct pid *pgrp)
 {
-	int retval = 0;
 	struct task_struct *p;
 
 	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
-		if (!task_is_stopped(p))
-			continue;
-		retval = 1;
-		break;
+		if (p->signal->flags & SIGNAL_STOP_STOPPED)
+			return true;
 	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
-	return retval;
+
+	return false;
 }
 
 /*
@@ -751,7 +738,7 @@ static void reparent_leader(struct task_struct *father, struct task_struct *p,
 {
 	list_move_tail(&p->sibling, &p->real_parent->children);
 
-	if (task_detached(p))
+	if (p->exit_state == EXIT_DEAD)
 		return;
 	/*
 	 * If this is a threaded reparent there is no need to
@@ -764,10 +751,9 @@ static void reparent_leader(struct task_struct *father, struct task_struct *p,
 	p->exit_signal = SIGCHLD;
 
 	/* If it has exited notify the new parent about this child's death. */
-	if (!task_ptrace(p) &&
+	if (!p->ptrace &&
 	    p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
-		do_notify_parent(p, p->exit_signal);
-		if (task_detached(p)) {
+		if (do_notify_parent(p, p->exit_signal)) {
 			p->exit_state = EXIT_DEAD;
 			list_move_tail(&p->sibling, dead);
 		}
@@ -794,7 +780,7 @@ static void forget_original_parent(struct task_struct *father)
 		do {
 			t->real_parent = reaper;
 			if (t->parent == father) {
-				BUG_ON(task_ptrace(t));
+				BUG_ON(t->ptrace);
 				t->parent = t->real_parent;
 			}
 			if (t->pdeath_signal)
@@ -819,8 +805,7 @@ static void forget_original_parent(struct task_struct *father)
  */
 static void exit_notify(struct task_struct *tsk, int group_dead)
 {
-	int signal;
-	void *cookie;
+	bool autoreap;
 
 	/*
 	 * This does two things:
@@ -851,26 +836,33 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
 	 * we have changed execution domain as these two values started
 	 * the same after a fork.
 	 */
-	if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
+	if (thread_group_leader(tsk) && tsk->exit_signal != SIGCHLD &&
 	    (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
 	     tsk->self_exec_id != tsk->parent_exec_id))
 		tsk->exit_signal = SIGCHLD;
 
-	signal = tracehook_notify_death(tsk, &cookie, group_dead);
-	if (signal >= 0)
-		signal = do_notify_parent(tsk, signal);
+	if (unlikely(tsk->ptrace)) {
+		int sig = thread_group_leader(tsk) &&
+				thread_group_empty(tsk) &&
+				!ptrace_reparented(tsk) ?
+			tsk->exit_signal : SIGCHLD;
+		autoreap = do_notify_parent(tsk, sig);
+	} else if (thread_group_leader(tsk)) {
+		autoreap = thread_group_empty(tsk) &&
+			do_notify_parent(tsk, tsk->exit_signal);
+	} else {
+		autoreap = true;
+	}
 
-	tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE;
+	tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;
 
 	/* mt-exec, de_thread() is waiting for group leader */
 	if (unlikely(tsk->signal->notify_count < 0))
 		wake_up_process(tsk->signal->group_exit_task);
 	write_unlock_irq(&tasklist_lock);
 
-	tracehook_report_death(tsk, signal, cookie, group_dead);
-
 	/* If the process is dead, release it - nobody will wait for it */
-	if (signal == DEATH_REAP)
+	if (autoreap)
 		release_task(tsk);
 }
 
@@ -923,7 +915,7 @@ NORET_TYPE void do_exit(long code)
 	 */
 	set_fs(USER_DS);
 
-	tracehook_report_exit(&code);
+	ptrace_event(PTRACE_EVENT_EXIT, code);
 
 	validate_creds_for_do_exit(tsk);
 
@@ -1235,9 +1227,9 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 	traced = ptrace_reparented(p);
 	/*
 	 * It can be ptraced but not reparented, check
-	 * !task_detached() to filter out sub-threads.
+	 * thread_group_leader() to filter out sub-threads.
 	 */
-	if (likely(!traced) && likely(!task_detached(p))) {
+	if (likely(!traced) && thread_group_leader(p)) {
 		struct signal_struct *psig;
 		struct signal_struct *sig;
 		unsigned long maxrss;
@@ -1345,16 +1337,13 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 		/* We dropped tasklist, ptracer could die and untrace */
 		ptrace_unlink(p);
 		/*
-		 * If this is not a detached task, notify the parent.
-		 * If it's still not detached after that, don't release
-		 * it now.
+		 * If this is not a sub-thread, notify the parent.
+		 * If parent wants a zombie, don't release it now.
 		 */
-		if (!task_detached(p)) {
-			do_notify_parent(p, p->exit_signal);
-			if (!task_detached(p)) {
-				p->exit_state = EXIT_ZOMBIE;
-				p = NULL;
-			}
+		if (thread_group_leader(p) &&
+		    !do_notify_parent(p, p->exit_signal)) {
+			p->exit_state = EXIT_ZOMBIE;
+			p = NULL;
 		}
 		write_unlock_irq(&tasklist_lock);
 	}
@@ -1367,7 +1356,8 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 static int *task_stopped_code(struct task_struct *p, bool ptrace)
 {
 	if (ptrace) {
-		if (task_is_stopped_or_traced(p))
+		if (task_is_stopped_or_traced(p) &&
+		    !(p->jobctl & JOBCTL_LISTENING))
 			return &p->exit_code;
 	} else {
 		if (p->signal->flags & SIGNAL_STOP_STOPPED)
@@ -1563,7 +1553,7 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
 		 * Notification and reaping will be cascaded to the real
 		 * parent when the ptracer detaches.
 		 */
-		if (likely(!ptrace) && unlikely(task_ptrace(p))) {
+		if (likely(!ptrace) && unlikely(p->ptrace)) {
 			/* it will become visible, clear notask_error */
 			wo->notask_error = 0;
 			return 0;
@@ -1606,8 +1596,7 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
 		 * own children, it should create a separate process which
 		 * takes the role of real parent.
 		 */
-		if (likely(!ptrace) && task_ptrace(p) &&
-		    same_thread_group(p->parent, p->real_parent))
+		if (likely(!ptrace) && p->ptrace && !ptrace_reparented(p))
 			return 0;
 
 		/*

kernel/fork.c

@@ -37,7 +37,6 @@
 #include <linux/swap.h>
 #include <linux/syscalls.h>
 #include <linux/jiffies.h>
-#include <linux/tracehook.h>
 #include <linux/futex.h>
 #include <linux/compat.h>
 #include <linux/kthread.h>
@@ -1340,7 +1339,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	}
 
 	if (likely(p->pid)) {
-		tracehook_finish_clone(p, clone_flags, trace);
+		ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
 
 		if (thread_group_leader(p)) {
 			if (is_child_reaper(pid))
@@ -1481,10 +1480,22 @@ long do_fork(unsigned long clone_flags,
 	}
 
 	/*
-	 * When called from kernel_thread, don't do user tracing stuff.
+	 * Determine whether and which event to report to ptracer.  When
+	 * called from kernel_thread or CLONE_UNTRACED is explicitly
+	 * requested, no event is reported; otherwise, report if the event
+	 * for the type of forking is enabled.
 	 */
-	if (likely(user_mode(regs)))
-		trace = tracehook_prepare_clone(clone_flags);
+	if (likely(user_mode(regs)) && !(clone_flags & CLONE_UNTRACED)) {
+		if (clone_flags & CLONE_VFORK)
+			trace = PTRACE_EVENT_VFORK;
+		else if ((clone_flags & CSIGNAL) != SIGCHLD)
+			trace = PTRACE_EVENT_CLONE;
+		else
+			trace = PTRACE_EVENT_FORK;
+
+		if (likely(!ptrace_event_enabled(current, trace)))
+			trace = 0;
+	}
 
 	p = copy_process(clone_flags, stack_start, regs, stack_size,
 			 child_tidptr, NULL, trace);
@@ -1508,26 +1519,26 @@ long do_fork(unsigned long clone_flags,
 		}
 
 		audit_finish_fork(p);
-		tracehook_report_clone(regs, clone_flags, nr, p);
 
 		/*
 		 * We set PF_STARTING at creation in case tracing wants to
 		 * use this to distinguish a fully live task from one that
-		 * hasn't gotten to tracehook_report_clone() yet.  Now we
-		 * clear it and set the child going.
+		 * hasn't finished SIGSTOP raising yet.  Now we clear it
+		 * and set the child going.
 		 */
 		p->flags &= ~PF_STARTING;
 
 		wake_up_new_task(p);
 
-		tracehook_report_clone_complete(trace, regs,
-						clone_flags, nr, p);
+		/* forking complete and child started to run, tell ptracer */
+		if (unlikely(trace))
+			ptrace_event(trace, nr);
 
 		if (clone_flags & CLONE_VFORK) {
 			freezer_do_not_count();
 			wait_for_completion(&vfork);
 			freezer_count();
-			tracehook_report_vfork_done(p, nr);
+			ptrace_event(PTRACE_EVENT_VFORK_DONE, nr);
 		}
 	} else {
 		nr = PTR_ERR(p);

mm/nommu.c

@@ -22,7 +22,6 @@
 #include <linux/pagemap.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
-#include <linux/tracehook.h>
 #include <linux/blkdev.h>
 #include <linux/backing-dev.h>
 #include <linux/mount.h>
@@ -1087,7 +1086,7 @@ static unsigned long determine_vm_flags(struct file *file,
 	 * it's being traced - otherwise breakpoints set in it may interfere
 	 * with another untraced process
 	 */
-	if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
+	if ((flags & MAP_PRIVATE) && current->ptrace)
 		vm_flags &= ~VM_MAYSHARE;
 
 	return vm_flags;

mm/oom_kill.c

@@ -339,8 +339,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
 				 * then wait for it to finish before killing
 				 * some other task unnecessarily.
 				 */
-				if (!(task_ptrace(p->group_leader) &
-							PT_TRACE_EXIT))
+				if (!(p->group_leader->ptrace & PT_TRACE_EXIT))
 					return ERR_PTR(-1UL);
 			}
 		}

security/apparmor/domain.c

@@ -67,7 +67,7 @@ static int may_change_ptraced_domain(struct task_struct *task,
 	int error = 0;
 
 	rcu_read_lock();
-	tracer = tracehook_tracer_task(task);
+	tracer = ptrace_parent(task);
 	if (tracer) {
 		/* released below */
 		cred = get_task_cred(tracer);

security/selinux/hooks.c

@@ -2053,7 +2053,7 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm)
 			u32 ptsid = 0;
 
 			rcu_read_lock();
-			tracer = tracehook_tracer_task(current);
+			tracer = ptrace_parent(current);
 			if (likely(tracer != NULL)) {
 				sec = __task_cred(tracer)->security;
 				ptsid = sec->sid;
@@ -5319,7 +5319,7 @@ static int selinux_setprocattr(struct task_struct *p,
 		   Otherwise, leave SID unchanged and fail. */
 		ptsid = 0;
 		task_lock(p);
-		tracer = tracehook_tracer_task(p);
+		tracer = ptrace_parent(p);
 		if (tracer)
 			ptsid = task_sid(tracer);
 		task_unlock(p);