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	diff --git a/sys/kern/kern_jail.c b/sys/kern/kern_jail.c
	--- a/sys/kern/kern_jail.c
	+++ b/sys/kern/kern_jail.c
	@@ -106,6 +106,7 @@
	.pr_path = "/",
	.pr_securelevel = -1,
	.pr_devfs_rsnum = 0,
	+ .pr_state = PRISON_STATE_ALIVE,
	.pr_childmax = JAIL_MAX,
	.pr_hostuuid = DEFAULT_HOSTUUID,
	.pr_children = LIST_HEAD_INITIALIZER(prison0.pr_children),
	@@ -663,7 +664,7 @@
	}
	ch_flags \|= jsf->new \| jsf->disable;
	}
	- if ((flags & (JAIL_CREATE \| JAIL_UPDATE \| JAIL_ATTACH)) == JAIL_CREATE
	+ if ((flags & (JAIL_CREATE \| JAIL_ATTACH)) == JAIL_CREATE
	&& !(pr_flags & PR_PERSIST)) {
	error = EINVAL;
	vfs_opterror(opts, "new jail must persist or attach");
	@@ -1198,6 +1199,7 @@
	/* This brings the parent back to life. */
	mtx_lock(&ppr->pr_mtx);
	refcount_acquire(&ppr->pr_uref);
	+ ppr->pr_state = PRISON_STATE_ALIVE;
	mtx_unlock(&ppr->pr_mtx);
	error = osd_jail_call(ppr, PR_METHOD_CREATE, opts);
	if (error) {
	@@ -1216,8 +1218,10 @@
	}

	pr = malloc(sizeof(*pr), M_PRISON, M_WAITOK \| M_ZERO);
	- refcount_init(&pr->pr_ref, 0);
	+ pr->pr_state = PRISON_STATE_INVALID;
	+ refcount_init(&pr->pr_ref, 1);
	refcount_init(&pr->pr_uref, 0);
	+ drflags \|= PD_DEREF;
	LIST_INIT(&pr->pr_children);
	mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF \| MTX_DUPOK);
	TASK_INIT(&pr->pr_task, 0, prison_complete, pr);
	@@ -1311,11 +1315,6 @@

	mtx_lock(&pr->pr_mtx);
	drflags \|= PD_LOCKED;
	- /*
	- * New prisons do not yet have a reference, because we do not
	- * want others to see the incomplete prison once the
	- * allprison_lock is downgraded.
	- */
	} else {
	/*
	* Grab a reference for existing prisons, to ensure they
	@@ -1737,14 +1736,17 @@
	prison_set_allow_locked(pr, tallow, 0);
	/*
	* Persistent prisons get an extra reference, and prisons losing their
	- * persist flag lose that reference. Only do this for existing prisons
	- * for now, so new ones will remain unseen until after the module
	- * handlers have completed.
	+ * persist flag lose that reference.
	*/
	born = !prison_isalive(pr);
	- if (!created && (ch_flags & PR_PERSIST & (pr_flags ^ pr->pr_flags))) {
	+ if (ch_flags & PR_PERSIST & (pr_flags ^ pr->pr_flags)) {
	if (pr_flags & PR_PERSIST) {
	prison_hold(pr);
	+ /*
	+ * This may make a dead prison alive again, but wait
	+ * to label it as such until after OSD calls have had
	+ * a chance to run (and perhaps to fail).
	+ */
	refcount_acquire(&pr->pr_uref);
	} else {
	drflags \|= PD_DEUREF;
	@@ -1752,7 +1754,6 @@
	}
	}
	pr->pr_flags = (pr->pr_flags & ~ch_flags) \| pr_flags;
	- pr->pr_flags &= ~PR_REMOVE;
	mtx_unlock(&pr->pr_mtx);
	drflags &= ~PD_LOCKED;

	@@ -1826,15 +1827,20 @@
	goto done_deref;
	}

	+ /*
	+ * A new prison is now ready to be seen; either it has gained a user
	+ * reference via persistence, or is about to gain one via attachment.
	+ */
	+ if (born) {
	+ drflags = prison_lock_xlock(pr, drflags);
	+ pr->pr_state = PRISON_STATE_ALIVE;
	+ }
	+
	/* Attach this process to the prison if requested. */
	if (flags & JAIL_ATTACH) {
	error = do_jail_attach(td, pr, prison_lock_xlock(pr, drflags));
	drflags &= ~(PD_LOCKED \| PD_LIST_XLOCKED);
	if (error) {
	- if (created) {
	- /* do_jail_attach has removed the prison. */
	- pr = NULL;
	- }
	vfs_opterror(opts, "attach failed");
	goto done_deref;
	}
	@@ -1852,22 +1858,6 @@

	td->td_retval[0] = pr->pr_id;

	- if (created) {
	- /*
	- * Add a reference to newly created persistent prisons
	- * (which was not done earlier so that the prison would
	- * not be publicly visible).
	- */
	- if (pr_flags & PR_PERSIST) {
	- drflags = prison_lock_xlock(pr, drflags);
	- refcount_acquire(&pr->pr_ref);
	- refcount_acquire(&pr->pr_uref);
	- } else {
	- /* Non-persistent jails need no further changes. */
	- pr = NULL;
	- }
	- }
	-
	done_deref:
	/* Release any temporary prison holds and/or locks. */
	if (pr != NULL)
	@@ -2332,7 +2322,7 @@
	prison_remove_one(struct prison *pr)
	{
	struct proc *p;
	- int drflags;
	+ int was_alive, drflags;

	drflags = PD_DEREF \| PD_LOCKED \| PD_LIST_XLOCKED;

	@@ -2340,7 +2330,8 @@
	* Mark the prison as doomed, so it doesn't accidentally come back
	* to life. It may still be explicitly brought back by jail_set(2).
	*/
	- pr->pr_flags \|= PR_REMOVE;
	+ was_alive = pr->pr_state == PRISON_STATE_ALIVE;
	+ pr->pr_state = PRISON_STATE_DYING;

	/* If the prison was persistent, it is not anymore. */
	if (pr->pr_flags & PR_PERSIST) {
	@@ -2361,9 +2352,14 @@
	return;
	}

	+ /* Tell modules this prison has died. */
	mtx_unlock(&pr->pr_mtx);
	+ drflags &= ~PD_LOCKED;
	+ if (was_alive)
	+ (void)osd_jail_call(pr, PR_METHOD_REMOVE, NULL);
	+
	sx_xunlock(&allprison_lock);
	- drflags &= ~(PD_LOCKED \| PD_LIST_XLOCKED);
	+ drflags &= ~PD_LIST_XLOCKED;
	/*
	* Kill all processes unfortunate enough to be attached to this prison.
	*/
	@@ -2429,7 +2425,7 @@
	* a process root from one prison, but attached to the jail
	* of another.
	*/
	- refcount_acquire(&pr->pr_ref);
	+ prison_hold(pr);
	refcount_acquire(&pr->pr_uref);
	drflags \|= PD_DEREF \| PD_DEUREF;
	mtx_unlock(&pr->pr_mtx);
	@@ -2721,6 +2717,12 @@
	* prison_free() won't re-submit the task.
	*/
	prison_hold(pr);
	+ mtx_lock(&pr->pr_mtx);
	+ KASSERT(!(pr->pr_flags & PR_COMPLETE_PROC),
	+ ("Redundant last reference in prison_proc_free (jid=%d)",
	+ pr->pr_id));
	+ pr->pr_flags \|= PR_COMPLETE_PROC;
	+ mtx_unlock(&pr->pr_mtx);
	taskqueue_enqueue(taskqueue_thread, &pr->pr_task);
	}
	}
	@@ -2735,14 +2737,14 @@
	int drflags;

	/*
	- * This could be called to release the last reference, or the
	- * last user reference; the existence of a user reference implies
	- * the latter. There will always be a reference to remove, as
	- * prison_proc_free adds one.
	+ * This could be called to release the last reference, or the last
	+ * user reference (plus the reference held in prison_proc_free).
	*/
	drflags = prison_lock_xlock(pr, PD_DEREF);
	- if (refcount_load(&pr->pr_uref) > 0)
	+ if (pr->pr_flags & PR_COMPLETE_PROC) {
	+ pr->pr_flags &= ~PR_COMPLETE_PROC;
	drflags \|= PD_DEUREF;
	+ }
	prison_deref(pr, drflags);
	}

	@@ -2777,7 +2779,8 @@
	flags \|= PD_DEREF;
	}
	flags = prison_lock_xlock(pr, flags);
	- if (refcount_release(&pr->pr_uref)) {
	+ if (refcount_release(&pr->pr_uref) &&
	+ pr->pr_state == PRISON_STATE_ALIVE) {
	/*
	* When the last user references goes,
	* this becomes a dying prison.
	@@ -2785,6 +2788,7 @@
	KASSERT(
	refcount_load(&prison0.pr_uref) > 0,
	("prison0 pr_uref=0"));
	+ pr->pr_state = PRISON_STATE_DYING;
	mtx_unlock(&pr->pr_mtx);
	flags &= ~PD_LOCKED;
	(void)osd_jail_call(pr,
	@@ -2812,6 +2816,7 @@
	KASSERT(
	refcount_load(&prison0.pr_ref) != 0,
	("prison0 pr_ref=0"));
	+ pr->pr_state = PRISON_STATE_INVALID;
	TAILQ_REMOVE(&allprison, pr, pr_list);
	LIST_REMOVE(pr, pr_sibling);
	TAILQ_INSERT_TAIL(&freeprison, pr,
	@@ -3078,9 +3083,7 @@
	prison_isalive(struct prison *pr)
	{

	- if (__predict_false(refcount_load(&pr->pr_uref) == 0))
	- return (false);
	- if (__predict_false(pr->pr_flags & PR_REMOVE))
	+ if (__predict_false(pr->pr_state != PRISON_STATE_ALIVE))
	return (false);
	return (true);
	}
	@@ -3096,6 +3099,8 @@
	prison_isvalid(struct prison *pr)
	{

	+ if (__predict_false(pr->pr_state == PRISON_STATE_INVALID))
	+ return (false);
	if (__predict_false(refcount_load(&pr->pr_ref) == 0))
	return (false);
	return (true);
	@@ -3760,8 +3765,7 @@
	bzero(xp, sizeof(*xp));
	xp->pr_version = XPRISON_VERSION;
	xp->pr_id = cpr->pr_id;
	- xp->pr_state = prison_isalive(cpr)
	- ? PRISON_STATE_ALIVE : PRISON_STATE_DYING;
	+ xp->pr_state = cpr->pr_state;
	strlcpy(xp->pr_path, prison_path(pr, cpr), sizeof(xp->pr_path));
	strlcpy(xp->pr_host, cpr->pr_hostname, sizeof(xp->pr_host));
	strlcpy(xp->pr_name, prison_name(pr, cpr), sizeof(xp->pr_name));
	@@ -4412,6 +4416,10 @@
	db_printf(" parent = %p\n", pr->pr_parent);
	db_printf(" ref = %d\n", pr->pr_ref);
	db_printf(" uref = %d\n", pr->pr_uref);
	+ db_printf(" state = %s\n",
	+ pr->pr_state == PRISON_STATE_ALIVE ? "alive" :
	+ pr->pr_state == PRISON_STATE_DYING ? "dying" :
	+ "invalid");
	db_printf(" path = %s\n", pr->pr_path);
	db_printf(" cpuset = %d\n", pr->pr_cpuset
	? pr->pr_cpuset->cs_id : -1);
	diff --git a/sys/sys/jail.h b/sys/sys/jail.h
	--- a/sys/sys/jail.h
	+++ b/sys/sys/jail.h
	@@ -88,9 +88,11 @@
	};
	#define XPRISON_VERSION 3

	-#define PRISON_STATE_INVALID 0
	-#define PRISON_STATE_ALIVE 1
	-#define PRISON_STATE_DYING 2
	+enum prison_state {
	+ PRISON_STATE_INVALID = 0, /* New prison, not ready to be seen */
	+ PRISON_STATE_ALIVE, /* Current prison, visible to all */
	+ PRISON_STATE_DYING /* Removed but holding resources, */
	+}; /* optionally visible. */

	/*
	* Flags for jail_set and jail_get.
	@@ -155,6 +157,7 @@
	* (m) locked by pr_mtx
	* (p) locked by pr_mtx, and also at least shared allprison_lock required
	* to update
	+ * (q) locked by both pr_mtx and allprison_lock
	* (r) atomic via refcount(9), pr_mtx and allprison_lock required to
	* decrement to zero
	*/
	@@ -185,7 +188,8 @@
	int pr_securelevel; /* (p) securelevel */
	int pr_enforce_statfs; /* (p) statfs permission */
	int pr_devfs_rsnum; /* (p) devfs ruleset */
	- int pr_spare[3];
	+ enum prison_state pr_state; /* (q) state in life cycle */
	+ int pr_spare[2];
	int pr_osreldate; /* (c) kern.osreldate value */
	unsigned long pr_hostid; /* (p) jail hostid */
	char pr_name[MAXHOSTNAMELEN]; /* (p) admin jail name */
	@@ -222,6 +226,8 @@
	/* by this jail or an ancestor */
	#define PR_IP6 0x04000000 /* IPv6 restricted or disabled */
	/* by this jail or an ancestor */
	+#define PR_COMPLETE_PROC 0x08000000 /* prison_complete called from */
	+ /* prison_proc_free, releases uref */

	/*
	* Flags for pr_allow

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