IPoIB: Test for NULL broadcast object in ipiob_mcast_join_finish()
IPoIB: Test for NULL broadcast object in ipiob_mcast_join_finish()

We saw a kernel oops in our regression testing when a multicast "join
finish" occurred just after the interface was -- this is
<https://bugs.openfabrics.org/show_bug.cgi?id=1040>.  The test
randomly causes the HCA physical port to go down then up.

The cause of this is that ipoib_mcast_join_finish() processing happen
just after ipoib_mcast_dev_flush() was invoked (in which case the
broadcast pointer is NULL).  This patch tests for and handles the case
where priv->broadcast is NULL.

Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@kernel.org>
Signed-off-by: Jack Morgenstein <067deeb0d1a5180729b0e79bbb5b609fc5bbbab4@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <91e9b5f7ca0bb6300133ed378670d64af90dde66@cisco.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs