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author | Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> | 2017-01-24 13:00:43 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2017-01-24 16:14:57 -0500 |
commit | 93f955aad4bacee5acebad141d1a03cd51f27b4e (patch) | |
tree | 3be1033d66d191d4e06ae66ffd3d2b2808e045eb /net/tipc | |
parent | 294628c1fe660b5c4ba4127df05ff2aa8c09a08a (diff) | |
download | linux-93f955aad4bacee5acebad141d1a03cd51f27b4e.tar.bz2 |
tipc: fix nametbl_lock soft lockup at node/link events
We trigger a soft lockup as we grab nametbl_lock twice if the node
has a pending node up/down or link up/down event while:
- we process an incoming named message in tipc_named_rcv() and
perform an tipc_update_nametbl().
- we have pending backlog items in the name distributor queue
during a nametable update using tipc_nametbl_publish() or
tipc_nametbl_withdraw().
The following are the call chain associated:
tipc_named_rcv() Grabs nametbl_lock
tipc_update_nametbl() (publish/withdraw)
tipc_node_subscribe()/unsubscribe()
tipc_node_write_unlock()
<< lockup occurs if an outstanding node/link event
exits, as we grabs nametbl_lock again >>
tipc_nametbl_withdraw() Grab nametbl_lock
tipc_named_process_backlog()
tipc_update_nametbl()
<< rest as above >>
The function tipc_node_write_unlock(), in addition to releasing the
lock processes the outstanding node/link up/down events. To do this,
we need to grab the nametbl_lock again leading to the lockup.
In this commit we fix the soft lockup by introducing a fast variant of
node_unlock(), where we just release the lock. We adapt the
node_subscribe()/node_unsubscribe() to use the fast variants.
Reported-and-Tested-by: John Thompson <thompa.atl@gmail.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc')
-rw-r--r-- | net/tipc/node.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/tipc/node.c b/net/tipc/node.c index 9d2f4c2b08ab..27753325e06e 100644 --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -263,6 +263,11 @@ static void tipc_node_write_lock(struct tipc_node *n) write_lock_bh(&n->lock); } +static void tipc_node_write_unlock_fast(struct tipc_node *n) +{ + write_unlock_bh(&n->lock); +} + static void tipc_node_write_unlock(struct tipc_node *n) { struct net *net = n->net; @@ -417,7 +422,7 @@ void tipc_node_subscribe(struct net *net, struct list_head *subscr, u32 addr) } tipc_node_write_lock(n); list_add_tail(subscr, &n->publ_list); - tipc_node_write_unlock(n); + tipc_node_write_unlock_fast(n); tipc_node_put(n); } @@ -435,7 +440,7 @@ void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr) } tipc_node_write_lock(n); list_del_init(subscr); - tipc_node_write_unlock(n); + tipc_node_write_unlock_fast(n); tipc_node_put(n); } |