4.16-stable review patch. If anyone has any objections, please let me know.
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From: Sowmini Varadhan sowmini.varadhan@oracle.com
commit 53d0e83f9329aa51dcc205b514dbee05cb4df309 upstream.
rds_tcp_connection allocation/free management has the potential to be called from __rds_conn_create after IRQs have been disabled, so spin_[un]lock_bh cannot be used with rds_tcp_conn_lock.
Bottom-halves that need to synchronize for critical sections protected by rds_tcp_conn_lock should instead use rds_destroy_pending() correctly.
Reported-by: syzbot+c68e51bb5e699d3f8d91@syzkaller.appspotmail.com Fixes: ebeeb1ad9b8a ("rds: tcp: use rds_destroy_pending() to synchronize netns/module teardown and rds connection/workq management") Signed-off-by: Sowmini Varadhan sowmini.varadhan@oracle.com Acked-by: Santosh Shilimkar santosh.shilimkar@oracle.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/rds/tcp.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
--- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -275,13 +275,14 @@ static int rds_tcp_laddr_check(struct ne static void rds_tcp_conn_free(void *arg) { struct rds_tcp_connection *tc = arg; + unsigned long flags;
rdsdebug("freeing tc %p\n", tc);
- spin_lock_bh(&rds_tcp_conn_lock); + spin_lock_irqsave(&rds_tcp_conn_lock, flags); if (!tc->t_tcp_node_detached) list_del(&tc->t_tcp_node); - spin_unlock_bh(&rds_tcp_conn_lock); + spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
kmem_cache_free(rds_tcp_conn_slab, tc); } @@ -311,13 +312,13 @@ static int rds_tcp_conn_alloc(struct rds rdsdebug("rds_conn_path [%d] tc %p\n", i, conn->c_path[i].cp_transport_data); } - spin_lock_bh(&rds_tcp_conn_lock); + spin_lock_irq(&rds_tcp_conn_lock); for (i = 0; i < RDS_MPATH_WORKERS; i++) { tc = conn->c_path[i].cp_transport_data; tc->t_tcp_node_detached = false; list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list); } - spin_unlock_bh(&rds_tcp_conn_lock); + spin_unlock_irq(&rds_tcp_conn_lock); fail: if (ret) { for (j = 0; j < i; j++) @@ -529,7 +530,7 @@ static void rds_tcp_kill_sock(struct net
rtn->rds_tcp_listen_sock = NULL; rds_tcp_listen_stop(lsock, &rtn->rds_tcp_accept_w); - spin_lock_bh(&rds_tcp_conn_lock); + spin_lock_irq(&rds_tcp_conn_lock); list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) { struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
@@ -542,7 +543,7 @@ static void rds_tcp_kill_sock(struct net tc->t_tcp_node_detached = true; } } - spin_unlock_bh(&rds_tcp_conn_lock); + spin_unlock_irq(&rds_tcp_conn_lock); list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) rds_conn_destroy(tc->t_cpath->cp_conn); } @@ -590,7 +591,7 @@ static void rds_tcp_sysctl_reset(struct { struct rds_tcp_connection *tc, *_tc;
- spin_lock_bh(&rds_tcp_conn_lock); + spin_lock_irq(&rds_tcp_conn_lock); list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) { struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
@@ -600,7 +601,7 @@ static void rds_tcp_sysctl_reset(struct /* reconnect with new parameters */ rds_conn_path_drop(tc->t_cpath, false); } - spin_unlock_bh(&rds_tcp_conn_lock); + spin_unlock_irq(&rds_tcp_conn_lock); }
static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,