From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> 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@xxxxxxxxxxxx Fixes: c1aabdf379bc ("can-gw: add netlink based CAN routing") Cc: linux-stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- net/can/gw.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/can/gw.c b/net/can/gw.c index 81650affa3fa..1867000f8a65 100644 --- a/net/can/gw.c +++ b/net/can/gw.c @@ -495,10 +495,11 @@ static int cgw_notifier(struct notifier_block *nb, hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) { 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); } } } @@ -939,10 +940,11 @@ static void cgw_remove_all_jobs(void) ASSERT_RTNL(); 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); } } static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) @@ -1006,10 +1008,11 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh) if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw))) continue; hlist_del(&gwj->list); cgw_unregister_filter(gwj); + synchronize_rcu(); kmem_cache_free(cgw_cache, gwj); err = 0; break; } -- 2.30.2
