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In revision 1.29 timeout() was converted to ng_callout().

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The difference is that the callout function installed via the
ng_callout() method is guaranteed to NOT fire after the shutdown
method was run (when a node is marked NGF_INVALID).  Also, the
shutdown method and the callout function are guaranteed to NOT
run at the same time, as both require the writer lock.  Thus
we can safely ignore a zero return value from ng_uncallout()
(callout_stop()) in shutdown methods, and go on with freeing
the node.

The said revision broke the node shutdown -- ng_bridge_timeout()
is no longer fired after ng_bridge_shutdown() was run, resulting
in a memory leak, dead nodes, and inability to unload the module.
Fix this by cancelling the callout on shutdown, and moving part
responsible for freeing a node resources from ng_bridge_timer()
to ng_bridge_shutdown().

Noticed by:	ru
Submitted by:	glebius, ru
This commit is contained in:
Ruslan Ermilov 2005-02-09 15:14:44 +00:00
parent 83307acd08
commit 195cf61776
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=141574
1 changed files with 9 additions and 15 deletions
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24
sys/netgraph/ng_bridge.c
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@ -754,16 +754,20 @@ ng_bridge_shutdown(node_p node)
const priv_p priv = NG_NODE_PRIVATE(node);
/*
* Shut down everything except the timer. There's no way to
* avoid another possible timeout event (it may have already
* been dequeued), so we can't free the node yet.
* Shut down everything including the timer. Even if the
* callout has already been dequeued and is about to be
* run, ng_bridge_timeout() won't be fired as the node
* is already marked NGF_INVALID, so we're safe to free
* the node now.
*/
KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
("%s: numLinks=%d numHosts=%d",
__func__, priv->numLinks, priv->numHosts));
ng_uncallout(&priv->timer, node);
NG_NODE_SET_PRIVATE(node, NULL);
NG_NODE_UNREF(node);
FREE(priv->tab, M_NETGRAPH_BRIDGE);
/* NGF_INVALID flag is now set so node will be freed at next timeout */
FREE(priv, M_NETGRAPH_BRIDGE);
return (0);
}
@ -956,8 +960,6 @@ ng_bridge_remove_hosts(priv_p priv, int linkNum)
* we decrement link->loopCount for those links being muted due to
* a detected loopback condition, and we remove any hosts from
* the hashtable whom we haven't heard from in a long while.
*
* If the node has the NGF_INVALID flag set, our job is to kill it.
*/
static void
ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
@ -967,14 +969,6 @@ ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
int counter = 0;
int linkNum;
/* If node was shut down, this is the final lingering timeout */
if (NG_NODE_NOT_VALID(node)) {
FREE(priv, M_NETGRAPH_BRIDGE);
NG_NODE_SET_PRIVATE(node, NULL);
NG_NODE_UNREF(node);
return;
}
/* Update host time counters and remove stale entries */
for (bucket = 0; bucket < priv->numBuckets; bucket++) {
struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);