IPoIB: Fix use-after-free of multicast object

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Fix a crash in ipoib_mcast_join_task().  (with help from Or Gerlitz)

Commit c8c2afe360 ("IPoIB: Use rtnl lock/unlock when changing device
flags") added a call to rtnl_lock() in ipoib_mcast_join_task(), which
is run from the ipoib_workqueue, and hence the workqueue can't be
flushed from the context of ipoib_stop().

In the current code, ipoib_stop() (which doesn't flush the workqueue)
calls ipoib_mcast_dev_flush(), which goes and deletes all the
multicast entries.  This takes place without any synchronization with
a possible running instance of ipoib_mcast_join_task() for the same
ipoib device, leading to a crash due to NULL pointer dereference.

Fix this by making sure that the workqueue is flushed before
ipoib_mcast_dev_flush() is called.  To make that possible, we move the
RTNL-lock wrapped code to ipoib_mcast_join_finish().

Signed-off-by: Patrick McHardy <kaber@trash.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

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This commit is contained in:

Patrick McHardy 2012-08-30 07:01:30 +00:00 • committed by Roland Dreier

parent 979570e029

commit bea1e22df4

2 changed files with 11 additions and 10 deletions

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2

drivers/infiniband/ulp/ipoib/ipoib_main.c

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19

drivers/infiniband/ulp/ipoib/ipoib_multicast.c

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