diff --git a/sys/compat/sys/siginfo.h b/sys/compat/sys/siginfo.h
index 78a20284b011..5ea83b82657b 100644
--- a/sys/compat/sys/siginfo.h
+++ b/sys/compat/sys/siginfo.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: siginfo.h,v 1.7 2019/06/30 08:49:21 martin Exp $	 */
+/*	$NetBSD: siginfo.h,v 1.8 2019/09/30 21:13:33 kamil Exp $	 */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -75,6 +75,14 @@ struct __ksiginfo32 {
 			int	_error;
 			uint64_t _args[8]; /* SYS_MAXSYSARGS */
 		} _syscall;
+
+		struct {
+			int	_pe_report_event;
+			union {
+				pid_t	_pe_other_pid;
+				lwpid_t	_pe_lwp;
+			} _option;
+		} _ptrace_state;
 	} _reason;
 };
 
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 9109b9462c34..1bf2f8d0bc77 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_exec.c,v 1.481 2019/09/17 15:19:27 christos Exp $	*/
+/*	$NetBSD: kern_exec.c,v 1.482 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.481 2019/09/17 15:19:27 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.482 2019/09/30 21:13:33 kamil Exp $");
 
 #include "opt_exec.h"
 #include "opt_execfmt.h"
@@ -1339,7 +1339,7 @@ execve_runproc(struct lwp *l, struct execve_data * restrict data,
 	/* posix_spawn(3) reports a single event with implied exec(3) */
 	if ((p->p_slflag & PSL_TRACED) && !is_spawn) {
 		mutex_enter(p->p_lock);
-		eventswitch(TRAP_EXEC);
+		eventswitch(TRAP_EXEC, 0, 0);
 		mutex_enter(proc_lock);
 	}
 
@@ -2249,7 +2249,7 @@ spawn_return(void *arg)
 		}
 
 		mutex_enter(p->p_lock);
-		eventswitch(TRAP_CHLD);
+		eventswitch(TRAP_CHLD, PTRACE_POSIX_SPAWN, p->p_oppid);
 	}
 
  cpu_return:
@@ -2630,8 +2630,7 @@ do_posix_spawn(struct lwp *l1, pid_t *pid_res, bool *child_ok, const char *path,
 	if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) ==
 	    (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) {
 		proc_changeparent(p2, p1->p_pptr);
-		p1->p_pspid = p2->p_pid;
-		p2->p_pspid = p1->p_pid;
+		p2->p_oppid = p1->p_pid;
 	}
 
 	LIST_INSERT_AFTER(p1, p2, p_pglist);
@@ -2685,7 +2684,7 @@ do_posix_spawn(struct lwp *l1, pid_t *pid_res, bool *child_ok, const char *path,
 		}
 
 		mutex_enter(p1->p_lock);
-		eventswitch(TRAP_CHLD);
+		eventswitch(TRAP_CHLD, PTRACE_POSIX_SPAWN, pid);
 	}
 	return 0;
 
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index f3c778f2bf03..217ea4cc44b0 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_fork.c,v 1.213 2019/06/13 20:20:18 kamil Exp $	*/
+/*	$NetBSD: kern_fork.c,v 1.214 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2001, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.213 2019/06/13 20:20:18 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.214 2019/09/30 21:13:33 kamil Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_dtrace.h"
@@ -252,7 +252,6 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
 	int		count;
 	vaddr_t		uaddr;
 	int		tnprocs;
-	bool		trace_fork, trace_vfork;
 	int		error = 0;
 
 	p1 = l1->l_proc;
@@ -511,17 +510,9 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
 	/*
 	 * Trace fork(2) and vfork(2)-like events on demand in a debugger.
 	 */
-	trace_fork = tracefork(p1, flags);
-	trace_vfork = tracevfork(p1, flags);
-	if (trace_fork || trace_vfork)
+	if (tracefork(p1, flags) || tracevfork(p1, flags)) {
 		proc_changeparent(p2, p1->p_pptr);
-	if (trace_fork) {
-		p1->p_fpid = p2->p_pid;
-		p2->p_fpid = p1->p_pid;
-	}
-	if (trace_vfork) {
-		p1->p_vfpid = p2->p_pid;
-		p2->p_vfpid = p1->p_pid;
+		p2->p_oppid = p1->p_pid;
 	}
 
 	LIST_INSERT_AFTER(p1, p2, p_pglist);
@@ -605,7 +596,9 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
 	 */
 	if (tracefork(p1, flags) || tracevfork(p1, flags)) {
 		mutex_enter(p1->p_lock);
-		eventswitch(TRAP_CHLD);
+		eventswitch(TRAP_CHLD,
+		    tracefork(p1, flags) ? PTRACE_FORK : PTRACE_VFORK,
+		    retval[0]);
 		mutex_enter(proc_lock);
 	}
 
@@ -621,8 +614,7 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
 	 */
 	if (tracevforkdone(p1, flags)) {
 		mutex_enter(p1->p_lock);
-		p1->p_vfpid_done = retval[0];
-		eventswitch(TRAP_CHLD);
+		eventswitch(TRAP_CHLD, PTRACE_VFORK_DONE, retval[0]);
 	} else
 		mutex_exit(proc_lock);
 
@@ -645,9 +637,10 @@ child_return(void *arg)
 			mutex_exit(proc_lock);
 			goto my_tracer_is_gone;
 		}
-
 		mutex_enter(p->p_lock);
-		eventswitch(TRAP_CHLD);
+		eventswitch(TRAP_CHLD,
+		    ISSET(p->p_lflag, PL_PPWAIT) ? PTRACE_VFORK : PTRACE_FORK,
+		    p->p_oppid);
 	}
 
 my_tracer_is_gone:
diff --git a/sys/kern/kern_lwp.c b/sys/kern/kern_lwp.c
index a7ecd53c8922..ab3a958c82f6 100644
--- a/sys/kern/kern_lwp.c
+++ b/sys/kern/kern_lwp.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_lwp.c,v 1.202 2019/06/04 11:54:03 kamil Exp $	*/
+/*	$NetBSD: kern_lwp.c,v 1.203 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 2001, 2006, 2007, 2008, 2009 The NetBSD Foundation, Inc.
@@ -211,7 +211,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.202 2019/06/04 11:54:03 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.203 2019/09/30 21:13:33 kamil Exp $");
 
 #include "opt_ddb.h"
 #include "opt_lockdebug.h"
@@ -239,6 +239,7 @@ __KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.202 2019/06/04 11:54:03 kamil Exp $")
 #include <sys/fstrans.h>
 #include <sys/dtrace_bsd.h>
 #include <sys/sdt.h>
+#include <sys/ptrace.h>
 #include <sys/xcall.h>
 #include <sys/uidinfo.h>
 #include <sys/sysctl.h>
@@ -1091,8 +1092,7 @@ lwp_exit(struct lwp *l)
 			 * about a terminating LWP as it would deadlock.
 			 */
 		} else {
-			p->p_lwp_exited = l->l_lid;
-			eventswitch(TRAP_LWP);
+			eventswitch(TRAP_LWP, PTRACE_LWP_EXIT, l->l_lid);
 			mutex_enter(proc_lock);
 		}
 	}
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index f7d75264484c..94f58bb95453 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_proc.c,v 1.234 2019/08/02 22:46:44 kamil Exp $	*/
+/*	$NetBSD: kern_proc.c,v 1.235 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.234 2019/08/02 22:46:44 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.235 2019/09/30 21:13:33 kamil Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_kstack.h"
@@ -2263,12 +2263,7 @@ fill_proc(const struct proc *psrc, struct proc *p, bool allowaddr)
 	COND_SET_VALUE(p->p_sigpend, psrc->p_sigpend, allowaddr);
 	COND_SET_VALUE(p->p_lwpctl, psrc->p_lwpctl, allowaddr);
 	p->p_ppid = psrc->p_ppid;
-	p->p_fpid = psrc->p_fpid;
-	p->p_vfpid = psrc->p_vfpid;
-	p->p_vfpid_done = psrc->p_vfpid_done;
-	p->p_lwp_created = psrc->p_lwp_created;
-	p->p_lwp_exited = psrc->p_lwp_exited;
-	p->p_pspid = psrc->p_pspid;
+	p->p_oppid = psrc->p_oppid;
 	COND_SET_VALUE(p->p_path, psrc->p_path, allowaddr);
 	COND_SET_VALUE(p->p_sigctx, psrc->p_sigctx, allowaddr);
 	p->p_nice = psrc->p_nice;
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index d2dbd6c28285..774c46f6e268 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_sig.c,v 1.364 2019/06/21 04:28:12 kamil Exp $	*/
+/*	$NetBSD: kern_sig.c,v 1.365 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -70,7 +70,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.364 2019/06/21 04:28:12 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.365 2019/09/30 21:13:33 kamil Exp $");
 
 #include "opt_ptrace.h"
 #include "opt_dtrace.h"
@@ -1560,7 +1560,7 @@ proc_stop_done(struct proc *p, int ppmask)
  * an event specific to a traced process only.
  */
 void
-eventswitch(int code)
+eventswitch(int code, int pe_report_event, int entity)
 {
 	struct lwp *l = curlwp;
 	struct proc *p = l->l_proc;
@@ -1605,8 +1605,12 @@ eventswitch(int code)
 
 	KSI_INIT_TRAP(&ksi);
 	ksi.ksi_lid = l->l_lid;
-	ksi.ksi_info._signo = signo;
-	ksi.ksi_info._code = code;
+	ksi.ksi_signo = signo;
+	ksi.ksi_code = code;
+	ksi.ksi_pe_report_event = pe_report_event;
+
+	CTASSERT(sizeof(ksi.ksi_pe_other_pid) == sizeof(ksi.ksi_pe_lwp));
+	ksi.ksi_pe_other_pid = entity;
 
 	/* Needed for ktrace */
 	ps = p->p_sigacts;
diff --git a/sys/kern/sys_lwp.c b/sys/kern/sys_lwp.c
index a4eaec05402b..be7844bd1b86 100644
--- a/sys/kern/sys_lwp.c
+++ b/sys/kern/sys_lwp.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: sys_lwp.c,v 1.69 2019/07/10 17:52:22 maxv Exp $	*/
+/*	$NetBSD: sys_lwp.c,v 1.70 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.69 2019/07/10 17:52:22 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.70 2019/09/30 21:13:33 kamil Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -45,6 +45,7 @@ __KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.69 2019/07/10 17:52:22 maxv Exp $");
 #include <sys/syscallargs.h>
 #include <sys/kauth.h>
 #include <sys/kmem.h>
+#include <sys/ptrace.h>
 #include <sys/sleepq.h>
 #include <sys/lwpctl.h>
 #include <sys/cpu.h>
@@ -91,8 +92,7 @@ mi_startlwp(void *arg)
 		}
 
 		mutex_enter(p->p_lock);
-		p->p_lwp_created = l->l_lid;
-		eventswitch(TRAP_LWP);
+		eventswitch(TRAP_LWP, PTRACE_LWP_CREATE, l->l_lid);
 	}
 }
 
diff --git a/sys/kern/sys_ptrace_common.c b/sys/kern/sys_ptrace_common.c
index 82df4fb88cea..2fa0be07981d 100644
--- a/sys/kern/sys_ptrace_common.c
+++ b/sys/kern/sys_ptrace_common.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: sys_ptrace_common.c,v 1.58 2019/07/18 20:10:46 kamil Exp $	*/
+/*	$NetBSD: sys_ptrace_common.c,v 1.59 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -118,7 +118,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_ptrace_common.c,v 1.58 2019/07/18 20:10:46 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_ptrace_common.c,v 1.59 2019/09/30 21:13:33 kamil Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ptrace.h"
@@ -694,27 +694,25 @@ ptrace_get_process_state(struct proc *t, void *addr, size_t data)
 		DPRINTF(("%s: %zu != %zu\n", __func__, data, sizeof(ps)));
 		return EINVAL;
 	}
-	memset(&ps, 0, sizeof(ps));
 
-	if (t->p_fpid) {
-		ps.pe_report_event = PTRACE_FORK;
-		ps.pe_other_pid = t->p_fpid;
-	} else if (t->p_vfpid) {
-		ps.pe_report_event = PTRACE_VFORK;
-		ps.pe_other_pid = t->p_vfpid;
-	} else if (t->p_vfpid_done) {
-		ps.pe_report_event = PTRACE_VFORK_DONE;
-		ps.pe_other_pid = t->p_vfpid_done;
-	} else if (t->p_lwp_created) {
-		ps.pe_report_event = PTRACE_LWP_CREATE;
-		ps.pe_lwp = t->p_lwp_created;
-	} else if (t->p_lwp_exited) {
-		ps.pe_report_event = PTRACE_LWP_EXIT;
-		ps.pe_lwp = t->p_lwp_exited;
-	} else if (t->p_pspid) {
-		ps.pe_report_event = PTRACE_POSIX_SPAWN;
-		ps.pe_other_pid = t->p_pspid;
+	if (t->p_sigctx.ps_info._signo != SIGTRAP ||
+	    (t->p_sigctx.ps_info._code != TRAP_CHLD &&
+	        t->p_sigctx.ps_info._code != TRAP_LWP)) {
+		return EINVAL;
 	}
+
+	ps.pe_report_event =
+		t->p_sigctx.ps_info._reason._ptrace_state._pe_report_event;
+
+	CTASSERT(sizeof(ps.pe_other_pid) ==
+	    sizeof(t->p_sigctx.ps_info._reason._ptrace_state._option._pe_other_pid));
+	CTASSERT(sizeof(ps.pe_lwp) ==
+	    sizeof(t->p_sigctx.ps_info._reason._ptrace_state._option._pe_other_pid));
+	CTASSERT(sizeof(ps.pe_other_pid) == sizeof(ps.pe_lwp));
+
+	ps.pe_other_pid =
+		t->p_sigctx.ps_info._reason._ptrace_state._option._pe_other_pid;
+
 	DPRINTF(("%s: lwp=%d event=%#x pid=%d lwp=%d\n", __func__,
 	    t->p_sigctx.ps_lwp, ps.pe_report_event,
 	    ps.pe_other_pid, ps.pe_lwp));
@@ -894,13 +892,6 @@ ptrace_sendsig(struct proc *t, struct lwp *lt, int signo, int resume_all)
 {
 	ksiginfo_t ksi;
 
-	t->p_fpid = 0;
-	t->p_vfpid = 0;
-	t->p_vfpid_done = 0;
-	t->p_lwp_created = 0;
-	t->p_lwp_exited = 0;
-	t->p_pspid = 0;
-
 	/* Finally, deliver the requested signal (or none). */
 	if (t->p_stat == SSTOP) {
 		/*
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 6e14e16b8978..ac562495f1e9 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: proc.h,v 1.355 2019/07/15 19:34:45 pgoyette Exp $	*/
+/*	$NetBSD: proc.h,v 1.356 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*-
  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -311,12 +311,7 @@ struct proc {
 	sigpend_t	p_sigpend;	/* p: pending signals */
 	struct lcproc	*p_lwpctl;	/* p, a: _lwp_ctl() information */
 	pid_t		p_ppid;		/* :: cached parent pid */
-	pid_t 		p_fpid;		/* :: forked pid */
-	pid_t 		p_vfpid;	/* :: vforked pid */
-	pid_t 		p_vfpid_done;	/* :: vforked done pid */
-	lwpid_t		p_lwp_created;	/* :: lwp created */
-	lwpid_t		p_lwp_exited;	/* :: lwp exited */
-	pid_t 		p_pspid;	/* :: posix_spawn pid */
+	pid_t		p_oppid;	/* :: cached original parent pid */
 	char		*p_path;	/* :: full pathname of executable */
 
 /*
diff --git a/sys/sys/siginfo.h b/sys/sys/siginfo.h
index 50d82c4ac78b..d1144c52ce9e 100644
--- a/sys/sys/siginfo.h
+++ b/sys/sys/siginfo.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: siginfo.h,v 1.33 2019/05/06 08:05:03 kamil Exp $	 */
+/*	$NetBSD: siginfo.h,v 1.34 2019/09/30 21:13:33 kamil Exp $	 */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -84,6 +84,14 @@ struct _ksiginfo {
 			int	_error;
 			uint64_t _args[8]; /* SYS_MAXSYSARGS */
 		} _syscall;
+
+		struct {
+			int	_pe_report_event;
+			union {
+				pid_t _pe_other_pid;
+				lwpid_t _pe_lwp;
+			} _option;
+		} _ptrace_state;
 	} _reason;
 };
 
@@ -167,6 +175,10 @@ typedef union siginfo {
 #define si_error	_info._reason._syscall._error
 #define si_args		_info._reason._syscall._args
 
+#define si_pe_report_event	_info._reason._ptrace_state._pe_report_event
+#define si_pe_other_pid	_info._reason._ptrace_state._option._pe_other_pid
+#define si_pe_lwp	_info._reason._ptrace_state._option._pe_lwp
+
 #ifdef _KERNEL
 /** Field access macros */
 #define	ksi_signo	ksi_info._signo
@@ -192,6 +204,10 @@ typedef union siginfo {
 #define ksi_retval	ksi_info._reason._syscall._retval
 #define ksi_error	ksi_info._reason._syscall._error
 #define ksi_args	ksi_info._reason._syscall._args
+
+#define ksi_pe_report_event	ksi_info._reason._ptrace_state._pe_report_event
+#define ksi_pe_other_pid	ksi_info._reason._ptrace_state._option._pe_other_pid
+#define ksi_pe_lwp		ksi_info._reason._ptrace_state._option._pe_lwp
 #endif /* _KERNEL */
 
 /** si_code */
diff --git a/sys/sys/signalvar.h b/sys/sys/signalvar.h
index 5963bb5992e2..1545d29bb455 100644
--- a/sys/sys/signalvar.h
+++ b/sys/sys/signalvar.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: signalvar.h,v 1.95 2019/09/08 11:53:23 mlelstv Exp $	*/
+/*	$NetBSD: signalvar.h,v 1.96 2019/09/30 21:13:33 kamil Exp $	*/
 
 /*
  * Copyright (c) 1991, 1993
@@ -152,7 +152,7 @@ void	killproc(struct proc *, const char *);
 void	setsigvec(struct proc *, int, struct sigaction *);
 int	killpg1(struct lwp *, struct ksiginfo *, int, int);
 void	proc_unstop(struct proc *p);
-void	eventswitch(int);
+void	eventswitch(int, int, int);
 void	sigswitch(int, int, bool);