Date: Sun, 3 May 2015 22:28:42 +0000 (UTC) From: Adrian Chadd <adrian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r282372 - head/sys/net80211 Message-ID: <201505032228.t43MSg1P059394@svn.freebsd.org>
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Author: adrian Date: Sun May 3 22:28:42 2015 New Revision: 282372 URL: https://svnweb.freebsd.org/changeset/base/282372 Log: Remove old iv_bss entry from the node table This may happen on RUN -> SCAN -> RUN -> SCAN state transition: 1. RUN -> SCAN: in ieee80211_sta_join1(): iv_bss will be moved to obss, refcnt will be reduced by 2 (default minimum). Now, if old iv_bss have some extra references (for example, from unacknowledged probe responses), it will not be freed and will stay in the node table. 2. SCAN -> RUN. 3. If old iv_bss will not be deleted by the time when the next RUN -> SCAN state transition occurs, then sta_leave() will reduce it's reference counter once more. As a result, two last users will free it -> this will lead to kernel panic. In this patch old iv_bss entry is explicitly removed from the node table in ieee80211_sta_join1() (as a result, it will not be processed by sta_leave()). PR: kern/199676 Differential Revision: Andriy Voskoboinyk <s3erios@gmail.com> Modified: head/sys/net80211/ieee80211_node.c Modified: head/sys/net80211/ieee80211_node.c ============================================================================== --- head/sys/net80211/ieee80211_node.c Sun May 3 22:13:55 2015 (r282371) +++ head/sys/net80211/ieee80211_node.c Sun May 3 22:28:42 2015 (r282372) @@ -93,6 +93,8 @@ static void node_getmimoinfo(const struc static void _ieee80211_free_node(struct ieee80211_node *); +static void node_reclaim(struct ieee80211_node_table *nt, + struct ieee80211_node *ni); static void ieee80211_node_table_init(struct ieee80211com *ic, struct ieee80211_node_table *nt, const char *name, int inact, int keymaxix); @@ -719,9 +721,15 @@ ieee80211_sta_join1(struct ieee80211_nod IEEE80211_ADDR_EQ(obss->ni_macaddr, selbs->ni_macaddr)); vap->iv_bss = selbs; /* NB: caller assumed to bump refcnt */ if (obss != NULL) { + struct ieee80211_node_table *nt = obss->ni_table; + copy_bss(selbs, obss); ieee80211_node_decref(obss); /* iv_bss reference */ - ieee80211_free_node(obss); /* station table reference */ + + IEEE80211_NODE_LOCK(nt); + node_reclaim(nt, obss); /* station table reference */ + IEEE80211_NODE_UNLOCK(nt); + obss = NULL; /* NB: guard against later use */ }
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