[src/trunk]: src/sys/ddb If we are DIAGNOSTIC don't try to go further if we f...

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

details:   https://anonhg.NetBSD.org/src/rev/597940aba1bd
branches:  trunk
changeset: 771759:597940aba1bd
user:      christos <christos%NetBSD.org@localhost>
date:      Sat Dec 03 16:25:49 2011 +0000

description:
If we are DIAGNOSTIC don't try to go further if we failed to take the
lock, because we are going to trigger a KASSERT. Also hold the lock
longer and take the proc lock for kpsignal(). Maybe we should add
mutex_steal() and mutex_return() for the debugger? Lock correction
suggestion from jmcneill.

diffstat:

 sys/ddb/db_xxx.c |  22 ++++++++++++++++------
 1 files changed, 16 insertions(+), 6 deletions(-)

diffs (52 lines):

diff -r 226807a7ef20 -r 597940aba1bd sys/ddb/db_xxx.c
--- a/sys/ddb/db_xxx.c  Sat Dec 03 10:53:09 2011 +0000
+++ b/sys/ddb/db_xxx.c  Sat Dec 03 16:25:49 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_xxx.c,v 1.65 2011/12/02 23:57:58 christos Exp $     */
+/*     $NetBSD: db_xxx.c,v 1.66 2011/12/03 16:25:49 christos Exp $     */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1991, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_xxx.c,v 1.65 2011/12/02 23:57:58 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_xxx.c,v 1.66 2011/12/03 16:25:49 christos Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_kgdb.h"
@@ -108,19 +108,29 @@
        }
        /* We might stop when the mutex is held or when not */
        t = mutex_tryenter(proc_lock);
+#ifdef DIAGNOSTIC
+       if (!t) {
+              db_error("could not acquire proc_lock mutex\n");
+              /*NOTREACHED*/
+       }
+#endif
        p = proc_find((pid_t)pid);
-       if (t)
-               mutex_exit(proc_lock);
        if (p == NULL) {
-              db_error("no such proc\n");
-              /*NOTREACHED*/
+               if (t)
+                       mutex_exit(proc_lock);
+               db_error("no such proc\n");
+               /*NOTREACHED*/
        }
        KSI_INIT(&ksi);
        ksi.ksi_signo = sig;
        ksi.ksi_code = SI_USER;
        ksi.ksi_pid = 0;
        ksi.ksi_uid = 0;
+       mutex_enter(p->p_lock);
        kpsignal2(p, &ksi);
+       mutex_exit(p->p_lock);
+       if (t)
+               mutex_exit(proc_lock);
 #else
        db_printf("This command is not currently supported.\n");
 #endif