Author: jamie
Date: Fri Aug 26 16:03:34 2011
New Revision: 225191
URL: http://svn.freebsd.org/changeset/base/225191
Log:
Delay the recursive decrement of pr_uref when jails are made invisible
but not removed; decrement it instead when the child jail actually
goes away. This avoids letting the counter go below zero in the case
where dying (pr_uref==0) jails are "resurrected", and an associated
KASSERT panic.
Submitted by: Steven Hartland
Approved by: re (bz)
MFC after: 1 week
Modified:
head/sys/kern/kern_jail.c
Modified: head/sys/kern/kern_jail.c
==============================================================================
--- head/sys/kern/kern_jail.c Fri Aug 26 15:24:54 2011 (r225190)
+++ head/sys/kern/kern_jail.c Fri Aug 26 16:03:34 2011 (r225191)
@@ -2470,32 +2470,11 @@ prison_deref(struct prison *pr, int flag
if (!(flags & PD_LOCKED))
mtx_lock(&pr->pr_mtx);
- /* Decrement the user references in a separate loop. */
- if (flags & PD_DEUREF) {
- for (tpr = pr;; tpr = tpr->pr_parent) {
- if (tpr != pr)
- mtx_lock(&tpr->pr_mtx);
- if (--tpr->pr_uref > 0)
- break;
- KASSERT(tpr != &prison0, ("prison0 pr_uref=0"));
- mtx_unlock(&tpr->pr_mtx);
- }
- /* Done if there were only user references to remove. */
- if (!(flags & PD_DEREF)) {
- mtx_unlock(&tpr->pr_mtx);
- if (flags & PD_LIST_SLOCKED)
- sx_sunlock(&allprison_lock);
- else if (flags & PD_LIST_XLOCKED)
- sx_xunlock(&allprison_lock);
- return;
- }
- if (tpr != pr) {
- mtx_unlock(&tpr->pr_mtx);
- mtx_lock(&pr->pr_mtx);
- }
- }
-
for (;;) {
+ if (flags & PD_DEUREF) {
+ pr->pr_uref--;
+ KASSERT(prison0.pr_uref != 0, ("prison0 pr_uref=0"));
+ }
if (flags & PD_DEREF)
pr->pr_ref--;
/* If the prison still has references, nothing else to do. */
@@ -2551,7 +2530,7 @@ prison_deref(struct prison *pr, int flag
/* Removing a prison frees a reference on its parent. */
pr = ppr;
mtx_lock(&pr->pr_mtx);
- flags = PD_DEREF;
+ flags = PD_DEREF | PD_DEUREF;
}
}
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
