From df791c54d627bae53c9be3be40a69594c55de487 Mon Sep 17 00:00:00 2001 From: Krishnamraju Eraparaju Date: Mon, 23 Sep 2019 15:41:12 +0530 Subject: [PATCH] RDMA/siw: Fix serialization issue in write_space() In siw_qp_llp_write_space(), 'sock' members should be accessed with sk_callback_lock held, otherwise, it could race with siw_sk_restore_upcalls(). And this could cause "NULL deref" panic. Below panic is due to the NULL cep returned from sk_to_cep(sk): Call Trace: siw_qp_llp_write_space+0x11/0x40 [siw] tcp_check_space+0x4c/0xf0 tcp_rcv_established+0x52b/0x630 tcp_v4_do_rcv+0xf4/0x1e0 tcp_v4_rcv+0x9b8/0xab0 ip_protocol_deliver_rcu+0x2c/0x1c0 ip_local_deliver_finish+0x44/0x50 ip_local_deliver+0x6b/0xf0 ? ip_protocol_deliver_rcu+0x1c0/0x1c0 ip_rcv+0x52/0xd0 ? ip_rcv_finish_core.isra.14+0x390/0x390 __netif_receive_skb_one_core+0x83/0xa0 netif_receive_skb_internal+0x73/0xb0 napi_gro_frags+0x1ff/0x2b0 t4_ethrx_handler+0x4a7/0x740 [cxgb4] process_responses+0x2c9/0x590 [cxgb4] ? t4_sge_intr_msix+0x1d/0x30 [cxgb4] ? handle_irq_event_percpu+0x51/0x70 ? handle_irq_event+0x41/0x60 ? handle_edge_irq+0x97/0x1a0 napi_rx_handler+0x14/0xe0 [cxgb4] net_rx_action+0x2af/0x410 __do_softirq+0xda/0x2a8 do_softirq_own_stack+0x2a/0x40 do_softirq+0x50/0x60 __local_bh_enable_ip+0x50/0x60 ip_finish_output2+0x18f/0x520 ip_output+0x6e/0xf0 ? __ip_finish_output+0x1f0/0x1f0 __ip_queue_xmit+0x14f/0x3d0 ? __slab_alloc+0x4b/0x58 __tcp_transmit_skb+0x57d/0xa60 tcp_write_xmit+0x23b/0xfd0 __tcp_push_pending_frames+0x2e/0xf0 tcp_sendmsg_locked+0x939/0xd50 tcp_sendmsg+0x27/0x40 sock_sendmsg+0x57/0x80 siw_tx_hdt+0x894/0xb20 [siw] ? find_busiest_group+0x3e/0x5b0 ? common_interrupt+0xa/0xf ? common_interrupt+0xa/0xf ? common_interrupt+0xa/0xf siw_qp_sq_process+0xf1/0xe60 [siw] ? __wake_up_common_lock+0x87/0xc0 siw_sq_resume+0x33/0xe0 [siw] siw_run_sq+0xac/0x190 [siw] ? remove_wait_queue+0x60/0x60 kthread+0xf8/0x130 ? siw_sq_resume+0xe0/0xe0 [siw] ? kthread_bind+0x10/0x10 ret_from_fork+0x35/0x40 Fixes: f29dd55b0236 ("rdma/siw: queue pair methods") Link: https://lore.kernel.org/r/20190923101112.32685-1-krishna2@chelsio.com Signed-off-by: Krishnamraju Eraparaju Reviewed-by: Bernard Metzler Signed-off-by: Jason Gunthorpe --- drivers/infiniband/sw/siw/siw_qp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/infiniband/sw/siw/siw_qp.c b/drivers/infiniband/sw/siw/siw_qp.c index 430314c8abd9..52d402f39df9 100644 --- a/drivers/infiniband/sw/siw/siw_qp.c +++ b/drivers/infiniband/sw/siw/siw_qp.c @@ -182,12 +182,19 @@ void siw_qp_llp_close(struct siw_qp *qp) */ void siw_qp_llp_write_space(struct sock *sk) { - struct siw_cep *cep = sk_to_cep(sk); + struct siw_cep *cep; - cep->sk_write_space(sk); + read_lock(&sk->sk_callback_lock); + + cep = sk_to_cep(sk); + if (cep) { + cep->sk_write_space(sk); - if (!test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) - (void)siw_sq_start(cep->qp); + if (!test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) + (void)siw_sq_start(cep->qp); + } + + read_unlock(&sk->sk_callback_lock); } static int siw_qp_readq_init(struct siw_qp *qp, int irq_size, int orq_size) -- 2.30.2