diff mbox series

[5.4,153/168] IB/hfi1, qib: Ensure RCU is locked when accessing list

Message ID 20200310123650.993669692@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH March 10, 2020, 12:39 p.m. UTC 
From: Dennis Dalessandro <dennis.dalessandro@intel.com>

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>

---
 drivers/infiniband/hw/hfi1/verbs.c    |    4 +++-
 drivers/infiniband/hw/qib/qib_verbs.c |    2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/infiniband/hw/hfi1/verbs.c
+++ b/drivers/infiniband/hw/hfi1/verbs.c
@@ -515,10 +515,11 @@  static inline void hfi1_handle_packet(st
 				       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))
@@ -527,6 +528,7 @@  static inline void hfi1_handle_packet(st
 				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.
--- a/drivers/infiniband/hw/qib/qib_verbs.c
+++ b/drivers/infiniband/hw/qib/qib_verbs.c
@@ -329,8 +329,10 @@  void qib_ib_rcv(struct qib_ctxtdata *rcd
 		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.