linux/drivers/infiniband/ulp
Shalom Lagziel 9c6f42e925 IB/ipoib: Fix sysfs Pkey create<->remove possible deadlock
A possible ABBA lock can happen with RTNL and vlan_rwsem.
For example:

Flow A: Device Flush
	__ipoib_ib_dev_flush
	down_read(vlan_rwsem) 			// Lock A
	ipoib_flush_ah
	flush_workqueue(priv->wq) 		// Wait for completion
	A work on shared WQ (Mcast carrier)
		ipoib_mcast_carrier_on_task
		while (!rtnl_trylock())         // Wait for lock B

Flow B: Sysfs PKEY delete
	ipoib_vlan_delete
	lock(RTNL) 				// Lock B
	down_write(vlan_rwsem) 			// Wait for lock A

This can happen with PKEY creates as well. The solution is to release
the RTNL lock in sysfs functions in case it is not possible to lock
VLAN RW semaphore and reset the SYS call.

Fixes: 69956d8326 ("IB/ipoib: Sync between remove_one to sysfs calls that use rtnl_lock")
Signed-off-by: Shalom Lagziel <shaloml@mellanox.com>
Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2017-09-25 11:47:23 -04:00
..
ipoib IB/ipoib: Fix sysfs Pkey create<->remove possible deadlock 2017-09-25 11:47:23 -04:00
iser IB: Correct MR length field to be 64-bit 2017-09-25 11:47:23 -04:00
isert RDMA: Remove useless MODULE_VERSION 2017-07-24 08:45:11 -04:00
opa_vnic RDMA/(core, ulp): Convert register/unregister event handler to be void 2017-08-24 16:27:10 -04:00
srp RDMA: Remove useless MODULE_VERSION 2017-07-24 08:45:11 -04:00
srpt RDMA/(core, ulp): Convert register/unregister event handler to be void 2017-08-24 16:27:10 -04:00
Makefile IB/opa-vnic: Virtual Network Interface Controller (VNIC) netdev 2017-04-20 12:01:38 -04:00