[src/trunk]: src/sys PR kern/52117: move stop code for debuged children after...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b708e79e6ef3
branches:  trunk
changeset: 822676:b708e79e6ef3
user:      martin <martin%NetBSD.org@localhost>
date:      Fri Mar 31 08:47:04 2017 +0000

description:
PR kern/52117: move stop code for debuged children after fork into MI code.
XXX we might want to revisit this when handling the same event for vfork
better.

diffstat:

 sys/arch/x86/x86/syscall.c |  16 ++--------------
 sys/kern/kern_fork.c       |  15 +++++++++++++--
 sys/kern/kern_sig.c        |  21 ++++++++++++++++-----
 3 files changed, 31 insertions(+), 21 deletions(-)

diffs (130 lines):

diff -r 4e500dbed6cc -r b708e79e6ef3 sys/arch/x86/x86/syscall.c
--- a/sys/arch/x86/x86/syscall.c        Fri Mar 31 08:38:13 2017 +0000
+++ b/sys/arch/x86/x86/syscall.c        Fri Mar 31 08:47:04 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: syscall.c,v 1.14 2016/07/07 06:55:40 msaitoh Exp $     */
+/*     $NetBSD: syscall.c,v 1.15 2017/03/31 08:47:04 martin Exp $      */
 
 /*-
  * Copyright (c) 1998, 2000, 2009 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: syscall.c,v 1.14 2016/07/07 06:55:40 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: syscall.c,v 1.15 2017/03/31 08:47:04 martin Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -65,18 +65,6 @@
 {
        struct lwp *l = arg;
        struct trapframe *tf = l->l_md.md_regs;
-       struct proc *p = l->l_proc;
-
-       if (p->p_slflag & PSL_TRACED) {
-               ksiginfo_t ksi;
-
-               mutex_enter(proc_lock);
-                KSI_INIT_EMPTY(&ksi);
-                ksi.ksi_signo = SIGTRAP;
-                ksi.ksi_lid = l->l_lid;
-                kpsignal(p, &ksi, NULL);
-               mutex_exit(proc_lock);
-       }
 
        X86_TF_RAX(tf) = 0;
        X86_TF_RFLAGS(tf) &= ~PSL_C;
diff -r 4e500dbed6cc -r b708e79e6ef3 sys/kern/kern_fork.c
--- a/sys/kern/kern_fork.c      Fri Mar 31 08:38:13 2017 +0000
+++ b/sys/kern/kern_fork.c      Fri Mar 31 08:47:04 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_fork.c,v 1.199 2017/01/13 23:00:35 kamil Exp $    */
+/*     $NetBSD: kern_fork.c,v 1.200 2017/03/31 08:47:04 martin 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 1.199 2017/01/13 23:00:35 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.200 2017/03/31 08:47:04 martin Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_dtrace.h"
@@ -500,6 +500,17 @@
        (*p2->p_emul->e_syscall_intern)(p2);
 #endif
 
+       /* if we are being traced, give the owner a chance to interfere */
+       if (p2->p_slflag & PSL_TRACED) {
+               ksiginfo_t ksi;
+
+                KSI_INIT_EMPTY(&ksi);
+               ksi.ksi_signo = SIGTRAP;
+               ksi.ksi_code = TRAP_CHLD;
+               ksi.ksi_lid = l2->l_lid;
+               kpsignal(p2, &ksi, NULL);
+       }
+
        /*
         * Update stats now that we know the fork was successful.
         */
diff -r 4e500dbed6cc -r b708e79e6ef3 sys/kern/kern_sig.c
--- a/sys/kern/kern_sig.c       Fri Mar 31 08:38:13 2017 +0000
+++ b/sys/kern/kern_sig.c       Fri Mar 31 08:47:04 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_sig.c,v 1.334 2017/03/24 17:40:44 christos Exp $  */
+/*     $NetBSD: kern_sig.c,v 1.335 2017/03/31 08:47:04 martin 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 1.334 2017/03/24 17:40:44 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.335 2017/03/31 08:47:04 martin Exp $");
 
 #include "opt_ptrace.h"
 #include "opt_dtrace.h"
@@ -1224,7 +1224,7 @@
        ksiginfo_t *kp;
        lwpid_t lid;
        sig_t action;
-       bool toall;
+       bool toall, debtrap = false;
        int error = 0;
 
        KASSERT(!cpu_intr_p());
@@ -1237,8 +1237,13 @@
         * If the process is being created by fork, is a zombie or is
         * exiting, then just drop the signal here and bail out.
         */
-       if (p->p_stat != SACTIVE && p->p_stat != SSTOP)
+       if (p->p_stat == SIDL && signo == SIGTRAP
+           && (p->p_slflag & PSL_TRACED)) {
+               /* allow an initial SIGTRAP for traced processes */
+               debtrap = true;
+       } else if (p->p_stat != SACTIVE && p->p_stat != SSTOP) {
                return 0;
+       }
 
        /* XXX for core dump/debugger */
        p->p_sigctx.ps_lwp = ksi->ksi_lid;
@@ -1353,7 +1358,13 @@
         * the signal to it.
         */
        if (lid != 0) {
-               l = lwp_find(p, lid);
+               if (__predict_false(debtrap)) {
+                       l = LIST_FIRST(&p->p_lwps);
+                       if (l->l_lid != lid)
+                               l = NULL;
+               } else {
+                       l = lwp_find(p, lid);
+               }
                if (l != NULL) {
                        if ((error = sigput(&l->l_sigpend, p, kp)) != 0)
                                goto out;