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93f955aad4
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>
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| .. | ||
| addr.c | ||
| addr.h | ||
| bcast.c | ||
| bcast.h | ||
| bearer.c | ||
| bearer.h | ||
| core.c | ||
| core.h | ||
| discover.c | ||
| discover.h | ||
| eth_media.c | ||
| ib_media.c | ||
| Kconfig | ||
| link.c | ||
| link.h | ||
| Makefile | ||
| monitor.c | ||
| monitor.h | ||
| msg.c | ||
| msg.h | ||
| name_distr.c | ||
| name_distr.h | ||
| name_table.c | ||
| name_table.h | ||
| net.c | ||
| net.h | ||
| netlink.c | ||
| netlink.h | ||
| netlink_compat.c | ||
| node.c | ||
| node.h | ||
| server.c | ||
| server.h | ||
| socket.c | ||
| socket.h | ||
| subscr.c | ||
| subscr.h | ||
| sysctl.c | ||
| udp_media.c | ||
| udp_media.h | ||