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Code Issues Releases Activity

Do not clear UN_ULOCK in certain case.

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Our vput calls vm_object_deallocate() --> vm_object_terminate().  The
vm_object_terminate() calls vn_lock(), since UN_LOCKED has been
already cleared in union_unlock().  Then, union_lock locks upper vnode
when UN_ULOCK is not set.  The upper vnode is not unlocked when
UN_KLOCK is set in union_unlock(), thus, union_lock tries to lock
locked vnode and we get panic.
This commit is contained in:
KATO Takenori 1997-04-26 04:09:40 +00:00
parent 9ca8226735
commit 928e13b6a1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=25160
2 changed files with 24 additions and 4 deletions
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14
sys/fs/unionfs/union_vnops.c
View File

@ -35,7 +35,7 @@
* SUCH DAMAGE.
*
* @(#)union_vnops.c 8.32 (Berkeley) 6/23/95
* $Id: union_vnops.c,v 1.26 1997/04/21 12:40:42 kato Exp $
* $Id: union_vnops.c,v 1.27 1997/04/21 15:32:24 kato Exp $
*/
#include <sys/param.h>
@ -1492,6 +1492,7 @@ union_lock(ap)
panic("union_link: upper vnode is locked, "
"but UN_UNLOCK is not set.");
#endif
printf("union_lock: adjust un_flags\n");
un->un_flags |= UN_ULOCK; /* Adjust -- dirty */
} else {
error = vn_lock(un->un_uppervp, flags, p);
@ -1565,7 +1566,16 @@ union_unlock(ap)
if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK)
VOP_UNLOCK(un->un_uppervp, 0, p);
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if ((un->un_flags & UN_KLOCK) && (ap->a_vp->v_usecount == 1)) {
/*
* Do not clear UN_ULOCK here. Our vput will call
* VOP_LOCK for vm related reason. If we clear UN_ULOCK,
* VOP_LOCK will try to lock upper vnode, whic is not
* unlocked.
*/
un->un_flags &= ~UN_KLOCK;
} else
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if (un->un_flags & UN_WANT) {
un->un_flags &= ~UN_WANT;

14
sys/miscfs/union/union_vnops.c
View File

@ -35,7 +35,7 @@
* SUCH DAMAGE.
*
* @(#)union_vnops.c 8.32 (Berkeley) 6/23/95
* $Id: union_vnops.c,v 1.26 1997/04/21 12:40:42 kato Exp $
* $Id: union_vnops.c,v 1.27 1997/04/21 15:32:24 kato Exp $
*/
#include <sys/param.h>
@ -1492,6 +1492,7 @@ union_lock(ap)
panic("union_link: upper vnode is locked, "
"but UN_UNLOCK is not set.");
#endif
printf("union_lock: adjust un_flags\n");
un->un_flags |= UN_ULOCK; /* Adjust -- dirty */
} else {
error = vn_lock(un->un_uppervp, flags, p);
@ -1565,7 +1566,16 @@ union_unlock(ap)
if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK)
VOP_UNLOCK(un->un_uppervp, 0, p);
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if ((un->un_flags & UN_KLOCK) && (ap->a_vp->v_usecount == 1)) {
/*
* Do not clear UN_ULOCK here. Our vput will call
* VOP_LOCK for vm related reason. If we clear UN_ULOCK,
* VOP_LOCK will try to lock upper vnode, whic is not
* unlocked.
*/
un->un_flags &= ~UN_KLOCK;
} else
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if (un->un_flags & UN_WANT) {
un->un_flags &= ~UN_WANT;