IB/hfi1, qib: Ensure RCU is locked when accessing list

commit 817a68a6584aa08e323c64283fec5ded7be84759 upstream.

The packet handling function, specifically the iteration of the qp list
for mad packet processing misses locking RCU before running through the
list. Not only is this incorrect, but the list_for_each_entry_rcu() call
can not be called with a conditional check for lock dependency. Remedy
this by invoking the rcu lock and unlock around the critical section.

This brings MAD packet processing in line with what is done for non-MAD
packets.

Fixes: 7724105686e7 ("IB/hfi1: add driver files")
Link: https://lore.kernel.org/r/20200225195445.140896.41873.stgit@awfm-01.aw.intel.com
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/infiniband/hw/hfi1/verbs.c b/drivers/infiniband/hw/hfi1/verbs.c
index 90e12f9433a39e42563d5dbdd2ed5876833ad70c..1cf1dfbf2596f150c9cf361a7817247725c94abf 100644 (file)
--- a/drivers/infiniband/hw/hfi1/verbs.c
+++ b/drivers/infiniband/hw/hfi1/verbs.c
@@ -595,10 +595,11 @@ static inline void hfi1_handle_packet(struct hfi1_packet *packet,
                                       opa_get_lid(packet->dlid, 9B));
                if (!mcast)
                        goto drop;
+               rcu_read_lock();
                list_for_each_entry_rcu(p, &mcast->qp_list, list) {
                        packet->qp = p->qp;
                        if (hfi1_do_pkey_check(packet))
-                               goto drop;
+                               goto unlock_drop;
                        spin_lock_irqsave(&packet->qp->r_lock, flags);
                        packet_handler = qp_ok(packet);
                        if (likely(packet_handler))
@@ -607,6 +608,7 @@ static inline void hfi1_handle_packet(struct hfi1_packet *packet,
                                ibp->rvp.n_pkt_drops++;
                        spin_unlock_irqrestore(&packet->qp->r_lock, flags);
                }
+               rcu_read_unlock();
                /*
                 * Notify rvt_multicast_detach() if it is waiting for us
                 * to finish.

diff --git a/drivers/infiniband/hw/qib/qib_verbs.c b/drivers/infiniband/hw/qib/qib_verbs.c
index 803c3544c75b5fbfbd3d8a35c96dcc3504e42ca8..5abbbb656a522831a3a92b557170461ecfa0c364 100644 (file)
--- a/drivers/infiniband/hw/qib/qib_verbs.c
+++ b/drivers/infiniband/hw/qib/qib_verbs.c
@@ -360,8 +360,10 @@ void qib_ib_rcv(struct qib_ctxtdata *rcd, void *rhdr, void *data, u32 tlen)
                if (mcast == NULL)
                        goto drop;
                this_cpu_inc(ibp->pmastats->n_multicast_rcv);
+               rcu_read_lock();
                list_for_each_entry_rcu(p, &mcast->qp_list, list)
                        qib_qp_rcv(rcd, hdr, 1, data, tlen, p->qp);
+               rcu_read_unlock();
                /*
                 * Notify rvt_multicast_detach() if it is waiting for us
                 * to finish.