[src/trunk]: src/sys/kern Avoid taking lwp_lock when calling process_sstep() ...

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

details:   https://anonhg.NetBSD.org/src/rev/cb0b13e63531
branches:  trunk
changeset: 933548:cb0b13e63531
user:      kamil <kamil%NetBSD.org@localhost>
date:      Tue May 26 23:08:56 2020 +0000

description:
Avoid taking lwp_lock when calling process_sstep() for sibling LWPs

This makes the code consistend between single-threaded and multi-threaded
code.

diffstat:

 sys/kern/sys_ptrace_common.c |  19 ++++++++-----------
 1 files changed, 8 insertions(+), 11 deletions(-)

diffs (41 lines):

diff -r 0491a4edd04d -r cb0b13e63531 sys/kern/sys_ptrace_common.c
--- a/sys/kern/sys_ptrace_common.c      Tue May 26 22:54:43 2020 +0000
+++ b/sys/kern/sys_ptrace_common.c      Tue May 26 23:08:56 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_ptrace_common.c,v 1.81 2020/05/23 23:42:43 ad Exp $        */
+/*     $NetBSD: sys_ptrace_common.c,v 1.82 2020/05/26 23:08:56 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 1.81 2020/05/23 23:42:43 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_ptrace_common.c,v 1.82 2020/05/26 23:08:56 kamil Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ptrace.h"
@@ -1421,16 +1421,13 @@
                 * the requested thread, and clear it for other threads.
                 */
                LIST_FOREACH(lt2, &t->p_lwps, l_sibling) {
-                       if (ISSET(lt2->l_pflag, LP_SINGLESTEP)) {
-                               lwp_lock(lt2);
-                               process_sstep(lt2, 1);
-                               lwp_unlock(lt2);
-                       } else if (lt != lt2) {
-                               lwp_lock(lt2);
-                               process_sstep(lt2, 0);
-                               lwp_unlock(lt2);
-                       }
+                       error = process_sstep(lt2,
+                           ISSET(lt2->l_pflag, LP_SINGLESTEP));
+                       if (error)
+                               break;
                }
+               if (error)
+                       break;
                error = process_sstep(lt,
                    ISSET(lt->l_pflag, LP_SINGLESTEP) || req == PT_STEP);
                if (error)