[src/trunk]: src/sys/kern In ksem_close_fop(), if we get a pshared semaphore ...

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

details:   https://anonhg.NetBSD.org/src/rev/e2fb9d6e63cc
branches:  trunk
changeset: 448553:e2fb9d6e63cc
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Tue Feb 05 07:14:32 2019 +0000

description:
In ksem_close_fop(), if we get a pshared semaphore that's not already
been marked dead, make sure we mark it so if the owner proc is the proc
closing it.  (This case can happen if a process sem_init()'s a pshared
semaphore and then exits without destroying it.)

Fixes kern/53942.

diffstat:

 sys/kern/uipc_sem.c |  18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diffs (41 lines):

diff -r 5c5491b12f70 -r e2fb9d6e63cc sys/kern/uipc_sem.c
--- a/sys/kern/uipc_sem.c       Tue Feb 05 06:46:47 2019 +0000
+++ b/sys/kern/uipc_sem.c       Tue Feb 05 07:14:32 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uipc_sem.c,v 1.52 2019/02/03 03:20:23 thorpej Exp $    */
+/*     $NetBSD: uipc_sem.c,v 1.53 2019/02/05 07:14:32 thorpej Exp $    */
 
 /*-
  * Copyright (c) 2011, 2019 The NetBSD Foundation, Inc.
@@ -60,7 +60,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uipc_sem.c,v 1.52 2019/02/03 03:20:23 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uipc_sem.c,v 1.53 2019/02/05 07:14:32 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -840,12 +840,18 @@
 {
        ksem_t *ks = fp->f_ksem;
 
-       if (ks->ks_pshared_id != 0 && ks->ks_pshared_proc != curproc) {
-               /* Do nothing if this is not the creator. */
-               return 0;
+       mutex_enter(&ks->ks_lock);
+
+       if (ks->ks_pshared_id) {
+               if (ks->ks_pshared_proc != curproc) {
+                       /* Do nothing if this is not the creator. */
+                       mutex_exit(&ks->ks_lock);
+                       return 0;
+               }
+               /* Mark this semaphore as dead. */
+               ks->ks_pshared_proc = NULL;
        }
 
-       mutex_enter(&ks->ks_lock);
        ksem_release(ks, -1);
        return 0;
 }