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authorSean Hefty <sean.hefty@intel.com>2011-02-23 08:17:40 -0800
committerRoland Dreier <roland@purestorage.com>2011-03-15 10:56:12 -0700
commit29963437a48475036353b95ab142bf199adb909e (patch)
tree23564281f4d60b7a9cdbaab5e1babe3f67cc8ca8
parent25ae21a10112875763c18b385624df713a288a05 (diff)
IB/cm: Bump reference count on cm_id before invoking callback
When processing a SIDR REQ, the ib_cm allocates a new cm_id. The refcount of the cm_id is initialized to 1. However, cm_process_work will decrement the refcount after invoking all callbacks. The result is that the cm_id will end up with refcount set to 0 by the end of the sidr req handler. If a user tries to destroy the cm_id, the destruction will proceed, under the incorrect assumption that no other threads are referencing the cm_id. This can lead to a crash when the cm callback thread tries to access the cm_id. This problem was noticed as part of a larger investigation with kernel crashes in the rdma_cm when running on a real time OS. Signed-off-by: Sean Hefty <sean.hefty@intel.com> Acked-by: Doug Ledford <dledford@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Roland Dreier <roland@purestorage.com>
-rw-r--r--drivers/infiniband/core/cm.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 64e0903091a8..1d9616be4192 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -2989,6 +2989,7 @@ static int cm_sidr_req_handler(struct cm_work *work)
goto out; /* No match. */
}
atomic_inc(&cur_cm_id_priv->refcount);
+ atomic_inc(&cm_id_priv->refcount);
spin_unlock_irq(&cm.lock);
cm_id_priv->id.cm_handler = cur_cm_id_priv->id.cm_handler;