On Wed, 2011-02-23 at 08:17 -0800, Hefty, Sean wrote: > 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 <[email protected]>
Acked-by: Doug Ledford <[email protected]> > --- > > drivers/infiniband/core/cm.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c > index 64e0903..1d9616b 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; > > -- Doug Ledford <[email protected]> GPG KeyID: CFBFF194 http://people.redhat.com/dledford Infiniband specific RPMs available at http://people.redhat.com/dledford/Infiniband
signature.asc
Description: This is a digitally signed message part
