From: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Date: Fri, 20 Jan 2012 18:43:54 +0000 (+0000)
Subject: RDMA/core: Fix kernel panic by always initializing qp->usecnt
X-Git-Tag: v3.2.6~65
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3ef7302303a7886fd1e6dea9dd33fe2c41784199;p=pandora-kernel.git

RDMA/core: Fix kernel panic by always initializing qp->usecnt

commit e47e321a35c741ee41b67976f8c6a3a7a42bc5c0 upstream.

We have just been investigating kernel panics related to
cq->ibcq.event_handler() completion calls.  The problem is that
ib_destroy_qp() fails with -EBUSY.

Further investigation revealed qp->usecnt is not initialized.  This
counter was introduced in linux-3.2 by commit 0e0ec7e0638e
("RDMA/core: Export ib_open_qp() to share XRC TGT QPs") but it only
gets initialized for IB_QPT_XRC_TGT, but it is checked in
ib_destroy_qp() for any QP type.

Fix this by initializing qp->usecnt for every QP we create.

Signed-off-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Signed-off-by: Sven Breuner <sven.breuner@itwm.fraunhofer.de>

[ Initialize qp->usecnt in uverbs too.  - Sean ]

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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