From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Fri, 18 Jun 2021 17:36:45 +0000 (+0200)
Subject: can: gw: synchronize rcu operations before removing gw job entry
X-Git-Tag: v4.4.276~66
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b8481db0d2e80fd974bd7169962a56422c56e358;p=thirdparty%2Fkernel%2Fstable.git

can: gw: synchronize rcu operations before removing gw job entry

commit fb8696ab14adadb2e3f6c17c18ed26b3ecd96691 upstream.

can_can_gw_rcv() is called under RCU protection, so after calling
can_rx_unregister(), we have to call synchronize_rcu in order to wait
for any RCU read-side critical sections to finish before removing the
kmem_cache entry with the referenced gw job entry.

Link: https://lore.kernel.org/r/20210618173645.2238-1-socketcan@hartkopp.net
Fixes: c1aabdf379bc ("can-gw: add netlink based CAN routing")
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/can/gw.c b/net/can/gw.c
index 81650affa3faa..1867000f8a650 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -497,6 +497,7 @@ static int cgw_notifier(struct notifier_block *nb,
 			if (gwj->src.dev == dev || gwj->dst.dev == dev) {
 				hlist_del(&gwj->list);
 				cgw_unregister_filter(gwj);
+				synchronize_rcu();
 				kmem_cache_free(cgw_cache, gwj);
 			}
 		}
@@ -941,6 +942,7 @@ static void cgw_remove_all_jobs(void)
 	hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
 		hlist_del(&gwj->list);
 		cgw_unregister_filter(gwj);
+		synchronize_rcu();
 		kmem_cache_free(cgw_cache, gwj);
 	}
 }
@@ -1008,6 +1010,7 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 		hlist_del(&gwj->list);
 		cgw_unregister_filter(gwj);
+		synchronize_rcu();
 		kmem_cache_free(cgw_cache, gwj);
 		err = 0;
 		break;