From: Ying Xue ying.xue@windriver.com
[ Upstream commit 557d054c01da0337ca81de9e9d9206d57245b57e ]
Until now, tipc_nametbl_unsubscribe() is called at subscriptions reference count cleanup. Usually the subscriptions cleanup is called at subscription timeout or at subscription cancel or at subscriber delete.
We have ignored the possibility of this being called from other locations, which causes deadlock as we try to grab the tn->nametbl_lock while holding it already.
CPU1: CPU2: ---------- ---------------- tipc_nametbl_publish spin_lock_bh(&tn->nametbl_lock) tipc_nametbl_insert_publ tipc_nameseq_insert_publ tipc_subscrp_report_overlap tipc_subscrp_get tipc_subscrp_send_event tipc_close_conn tipc_subscrb_release_cb tipc_subscrb_delete tipc_subscrp_put tipc_subscrp_put tipc_subscrp_kref_release tipc_nametbl_unsubscribe spin_lock_bh(&tn->nametbl_lock) <<grab nametbl_lock again>>
CPU1: CPU2: ---------- ---------------- tipc_nametbl_stop spin_lock_bh(&tn->nametbl_lock) tipc_purge_publications tipc_nameseq_remove_publ tipc_subscrp_report_overlap tipc_subscrp_get tipc_subscrp_send_event tipc_close_conn tipc_subscrb_release_cb tipc_subscrb_delete tipc_subscrp_put tipc_subscrp_put tipc_subscrp_kref_release tipc_nametbl_unsubscribe spin_lock_bh(&tn->nametbl_lock) <<grab nametbl_lock again>>
In this commit, we advance the calling of tipc_nametbl_unsubscribe() from the refcount cleanup to the intended callers.
Fixes: d094c4d5f5c7 ("tipc: add subscription refcount to avoid invalid delete") Reported-by: John Thompson thompa.atl@gmail.com Acked-by: Jon Maloy jon.maloy@ericsson.com Signed-off-by: Ying Xue ying.xue@windriver.com Signed-off-by: Parthasarathy Bhuvaragan parthasarathy.bhuvaragan@ericsson.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@verizon.com --- net/tipc/subscr.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c index 9d94e65d0894..271cd66e4b3b 100644 --- a/net/tipc/subscr.c +++ b/net/tipc/subscr.c @@ -141,6 +141,11 @@ void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower, static void tipc_subscrp_timeout(unsigned long data) { struct tipc_subscription *sub = (struct tipc_subscription *)data; + struct tipc_subscriber *subscriber = sub->subscriber; + + spin_lock_bh(&subscriber->lock); + tipc_nametbl_unsubscribe(sub); + spin_unlock_bh(&subscriber->lock);
/* Notify subscriber of timeout */ tipc_subscrp_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper, @@ -173,7 +178,6 @@ static void tipc_subscrp_kref_release(struct kref *kref) struct tipc_subscriber *subscriber = sub->subscriber;
spin_lock_bh(&subscriber->lock); - tipc_nametbl_unsubscribe(sub); list_del(&sub->subscrp_list); atomic_dec(&tn->subscription_count); spin_unlock_bh(&subscriber->lock); @@ -205,6 +209,7 @@ static void tipc_subscrb_subscrp_delete(struct tipc_subscriber *subscriber, if (s && memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) continue;
+ tipc_nametbl_unsubscribe(sub); tipc_subscrp_get(sub); spin_unlock_bh(&subscriber->lock); tipc_subscrp_delete(sub);